Everyone knows the story of Galileo. He is the avatar of the brave rationalist who stands tall against the stupidity and oppression of religious ignoramuses and ultimately triumphs through the power of science and reason. As such, his story is the pinnacle of much anti-religious historical argument: the ultimate example and crowning symbol of the eternal conflict between religion and science and evidence of the stultifying and suffocating effect of religion. Because everyone knows his story, he and elements of his tale can be invoked by anti-theistic polemicists without fear of any questioning or need for elaboration. However, the story of Galileo that everyone “knows” is substantially nonsense and is largely an Enlightenment fiction that became a nineteenth century moral fairy tale. Unfortunately, and as ever, the real history of the Galileo Affair is complex, nuanced, messy and not at all conducive to neat and convenient fables. This means the story of Galileo that “everyone knows” is mostly completely wrong.

In discussions about the relationship between science and religion, the role of the Catholic Church in history or even dissenters in the face of authority, the case of Galileo Galilei (1564-1642) gets invoked as an undeniable symbol of a brave rationalist who was persecuted by a dominant institution and ultimately vindicated. For anti-religious polemicists, if the Conflict Thesis is the historical framework for all understanding of the relationship between science and religion, the Galileo Affair is its central episode: the fixed point around which all other anti-theistic historiography revolves. The story of Galileo is so well-known and widely understood that it only needs to be briefly invoked or referred to; it is the beginning and end of the argument regarding the failings of religion and the triumph of science and reason.

Unfortunately the story of Galileo that everyone knows and which most polemicists invoke bears very little resemblance to anything that happened historically. Most elements of it are oversimplified and distorted or things that simply did not happen at all. It is a vastly complex story, requiring careful understanding of early cosmology and astronomy, theology, the Reformation and Counter-Reformation, the dynamics of Early Modern court politics and the complicated hierarchies of universities and the Church in the early seventeenth century. These are abstruse subjects and things most people never study. How they come together to allow us to actually understand the Galileo Affair requires years of reading of specialised scholarship: something almost none of those who invoke Galileo so glibly ever bother to do.

The standard polemical uses of this mythological version of the Galileo story are made up of most or all of the following five elements:

1. “Galileo proved that heliocentrism was true.” – Galileo’s telescopic discoveries and scientific arguments proved that the Earth rotated and that it orbited the Sun. His discoveries established heliocentrism scientifically and were accepted by scientists.
2. “The Catholic Church rejected Galileo’s scientific proofs and clung to a literal interpretation of the Bible.” – The Church and the Inquisition were scientifically illiterate or simply rejected Galileo’s science out of dogmatism and some even refused to look through his telescope and see his evidence with their own eyes.
3. “The Church regarded heliocentrism as heresy and persecuted anyone who argued for it.” – The dogmatic rejection of heliocentrism meant anyone who proposed it was persecuted by the Inquisition and in danger of being burned at the stake as a heretic.
4. “Galileo was hauled before the Inquisition where he bravely defended his scientific proofs.” – Galileo defended his science before the Inquisition and only recanted because he was threatened with torture and ran the risk of being burned at the stake.
5. “The Catholic Church only finally admitted Galileo was right in 1992.” – The Church continued to reject the science behind heliocentrism until 1992, when Pope John Paul II admitted Galileo was right for the first time, apologised to him and pardoned him.

These elements make up a satisfyingly symmetrical story, with a brave hero, wicked and stupid villains, a clear conflict between science and religion, a tragic climax and ultimate vindication and victory. But it is a mythic story and a moral fairy tale, not history. So it is almost entirely wrong.

“Galileo proved that heliocentrism was true.”

“Galileo’s telescopic discoveries and scientific arguments proved that the Earth rotated and that it orbited the Sun. His discoveries established heliocentrism scientifically and were accepted by scientists.“

The idea that Galileo proved heliocentrism is central to the mythic version of the Galileo story. Here we have the man often dubbed “the Father of Science” using direct observation via a telescope and pure scientific reason to show that the old Ptolemaic model was wrong, only to have the Catholic Church reject his science in favour of dogma. But Galileo did not prove that heliocentrism was true. He never claimed to have done so and made arguments to work around the fact that it had not been demonstrated, by him or by anyone else.

In 1615 the Chief Inquisitor, Cardinal Robert Bellarmine, ruled against Paolo Foscarini’s objections to his book on heliocentrism and theology being banned (see below). In his ruling, Bellarmine noted that if heliocentrism were demonstrated then some Scriptural texts would need to be reinterpreted. But he then observed “but I will not believe that there is such a demonstration, until it is shown me.” (Bellarmine, “Letter to Foscarini”, April 12, 1615) This was Bellarmine’s slightly wry way of saying that, as Foscarini knew, heliocentrism had been argued for but not proven.

Galileo knew this too. Not long after Bellarmine’s letter was widely circulated, Galileo wrote extensive private notes on its arguments, detailing how and why he disagreed with the cardinal. He acknowledged the point about heliocentrism being not yet demonstrated but laid out an argument as to why it should still not be rejected despite this:

It is the highest prudence to believe that there is no demonstration of the mobility of the Earth until such a proof has been given. And we do not ask anyone to believe this point without a demonstration. Rather we ask, for the good of the Holy Church, that what the followers of this doctrine know and can offer be examined with the greatest care, and that nothing be admitted unless it has a force which is greatly superior to the reasons on the other side. If the proponents were to have no more than ninety percent of the arguments on their side, they would be rebutted. But when everything offered by the philosophers and astronomers on the other side is proven to be for the most part false and without any importance, then the position of the proponents should not be scorned and be considered to be a paradox because of the fact that it cannot be demonstrated conclusively. And indeed this can be a great advantage. For it is clear that those who are on the false side cannot  have any argument or evidence of value; while on the side of truth, there is the advantage that everything agrees and is consistent. (Quoted in Richard J. Blackwell, Galileo, Bellarmine and the Bible, University of Notre Dame Press, 1991, Appendix IX, p. 271)

So here Galileo acknowledges heliocentrism has not been, and possibly cannot be, “demonstrated conclusively” and argues it “should not be scorned” on this basis, but to be considered on the overall weight of evidence. This is not an argument he would make if he believed it had been demonstrated, rather than simply argued for, even if he considered those arguments to be the better ones. At no point did Galileo claim heliocentrism had been “proven”.

So where does the popular misconception that he had proven heliocentrism come from? It appears to be based on the idea that there were just two competing cosmological models at the time: the traditional, geocentric Ptolemaic model and the newer, heliocentric Copernican alternative. Galileo’s telescopic observations of the phases of Venus could not be accommodated by the Ptolemaic model and effectively debunked that model and so, according to pop history accounts, this showed heliocentrism was true.

Except this is not correct. At the time there were no less than seven possible cosmological models available, not just two.

1. The Ptolemaic Model
2. The Heracleidian Model (also called the Egyptian Model)
3. The Copernican Model
4. The Tychonian Model
5. The Ursine Model
6. The Gilbertine Model
7. The Keplerian Model

Of these, the Ptolemaic model had long since predominated over its ancient alternatives: the largely lost geoheliocentric model of Heracleidus Ponticus and the wholly lost heliocentric model of Aristarchus. The latter was roundly rejected by the ancients and so we know nothing much about it. The Heracleidian model was partially known via some Late Roman texts, like Macrobius, but not highly regarded. The other five on the list above were much more recent: the Copernican (1514, 1543), the Tychonian (1587), the Ursine (1587), the Gilbertine (1600) and the Keplerian (1609). Of these, the Ursine and Gilbertine systems never gained much traction and the Keplerian one eventually did, but only well after Galileo’s time.

The problem this plethora of models poses for the common understanding of the history of heliocentrism is that, while the widely accepted Ptolemaic model and the marginal Gilbertine model could not accommodate the newly discovered phases of Venus, all of the five other models could. So the phases of Venus did not settle the ongoing debate about which of these models was correct.

Galileo chose to support the Copernican model because he thought the weight of evidence supported both the rotation of the Earth and its orbit around the Sun. He was aware of Kepler’s heliocentric alternative and corresponded with Kepler, but largely ignored the model that was, in the end, to turn out to be the most accurate. Many non-astronomers stuck with the Ptolemaic model out of philosophical conservatism and seem to have hoped the astronomers would sort out the scientific problems with it eventually. Virtually everyone in the early seventeenth century paid little attention to Kepler’s cosmology, largely because its elliptical orbits contradicted deeply ingrained ancient Greek ideas about the purity and nobility of a system of circles and spheres. But most astronomers did not favour the Copernican model, as Galileo did, but preferred the Tychonian alternative.

Developed by the remarkable astronomer Tycho Brahe, this was a geoheliocentric model; with the Earth at the centre, the Sun going around the Earth and the other planets orbiting the Sun. This may seem odd to us, but at the time it fitted the data better than all the alternatives and had the added advantage of not running counter to other accepted ideas and observations.

To begin with, unlike the Copernican system, the Tychonian model did not contradict accepted Aristotelian physics. There were seeming physical problems with both a rotating and an orbiting Earth, with attempts at observing the effects of the earth’s motion failing. Copernicans like Galileo had answers for why this was so, but did not have evidence that demonstrated the Earth’s movement. Even more significant was the lack of any observable Stellar Parallax.

If the Earth orbited the Sun, Tycho and others argued, we should be able to observe and measure the apparent shift in the position of the stars over the course of a year: this being a seeming shift caused by the actual movement of the Earth. But no such shift could be observed at all, let alone measured. Again, Copernicans like Galileo had an answer: the shift is small and so impossible to detect because the stars are an immense distance away. This was correct, but impossible to prove with the observations available in the early seventeenth century, even after the invention of telescopes. As it happened, James Bradley was the first to observe stellar parallax in the star Gamma Draconis in 1727 and Friedrich Wilhelm Bessel published his accurate measurement of parallax in the star 61 Cygni in 1838. The problem with the Copernican defence was that it was resorting to a hypothesis to defend a hypothesis, which most astronomers found distinctly unconvincing.

For these and a number of other reasons most astronomers of the late sixteenth and early seventeenth centuries preferred the Tychonian model over all alternatives. Kepler himself acknowledges this in his Harmonices Mundi (1619), where he defends heliocentrism and notes “the hypotheses of Copernicus and Tycho Brahe are alternatives; but Ptolemy’s antiquated views have been publicly rejected.” He goes on to admit that for “the mass of the intelligentsia” (apud vulgus studiosorum) a heliocentric view was still “heard by most of them as absurd” (auditu plerisque absurdissimum), meaning that for the majority of his learned readers the Tychonian model was the preferred option.

This remained the case well into the seventeenth century. In 1651 the astronomer Giovanni Battista Riccioli published his massive Almagestum Novum: over 1500 folio pages of detailed arguments and counter-arguments pitting the Ptolemaic, Copernican and Tychonian systems against each other (Kepler was, yet again, ignored). Riccioli weighed up the scientific, philosophical and theological arguments for and against all three and, like Kepler, judged that the Ptolemaic system was to be rejected. He then assessed that, on balance, the Tychonian system was superior to the Copernican alternative and did so substantially on scientific grounds. As Christopher M. Graney details in his Setting Aside All Authority: Giovanni Battista Riccioli and the Science against Copernicus in the Age of Galileo (University of Notre Dame Press, 2022), both Copernicans and their opponents marshalled theological and Biblical arguments in support of their favoured models, but overall the debate was based on science. And in Galileo’s time and for some decades after his death, the scientific consensus was heavily against heliocentrism.

Just how substantial that consensus was can be shown by a survey of responses to Copernicus in the century leading up to the Galileo Affair. Robert S. Westman’s analysis of writings from 1514 to 1600 turns up just 11 writers who accepted Copernicanism as something other than a calculating device in this period: Thomas Digges and Thomas Hariot in England; Giordano Bruno and Galileo Galilei in Italy; Diego de Zuñiga in Spain; Simon Stevin in the Low Countries; and Georg Joachim Rheticus, Michael Maestlin, Christoph Rothmann, and Johannes Kepler in Germany, though it seems Rothmann later changed his mind (Westman, “The Astronomer’s Role in the Sixteenth Century: A Preliminary Study,” History of Science, 18 (1980): 105-147, p. 106). Pietro Daniel Omodeo undertakes an even more detailed survey in his Copernicus in the Cultural Debates of the Renaissance: Reception, Legacy, Transformation (Brill, History of Science and Medicine Library / Medieval and Early Modern Science, 23, 45, 2014) and arrives at much the same conclusion, though he would argue the English scholar John Feild could possibly be added to the total. If we take the date right up to 1616, the eve of Galileo’s first encounter with the Roman Inquisition, we can also add William Lower and Paolo Foscarini.

This means that over the century before the Galileo Affair, out of all the thousands of astronomers, astrologers and natural philosophers across Europe, only somewhere between 12 and 14 scholars actually accepted heliocentrism. The pop history conception that the scientists were lined up behind Galileo in a confrontation with the Church is a long way from the truth. In fact, the Church had the consensus of science firmly on its side. And they knew it.

The Catholic Church rejected Galileo’s scientific proofs and clung to a literal interpretation of the Bible.”

“The Church and the Inquisition were scientifically illiterate or simply rejected Galileo’s science out of dogmatism and some even refused to look through his telescope and see his evidence with their own eyes.”

So Galileo did not prove heliocentrism and most of the scientists of his day did not agree with him that it was the better option out of several competing models. But another part of the mythic version of the Galileo story is that the churchmen who opposed him were scientifically illiterate or simply uninterested in the science behind the question. According to this part of the fairy tale of Galileo, they clung dogmatically to purely theological arguments.

It should be noted that several of the astronomers and scholars already mentioned were themselves churchmen. Diego de Zuñiga was an Augustinian friar, Paolo Foscarini was a Carmelite priest and Giovanni Battista Riccioli was a Jesuit. This should not be surprising, given that clergy in this period had the education, time and resources to pursue higher study and maintain a network of contacts with academics and scholars across Europe. In Catholic countries and actually across all of Europe, ecclesiastical office was a clear path for the academically gifted and one that could lead to high status, influence and genuine power. As a result, some of the most intelligent and highly educated men in Europe were found among the clergy and it was a way non-aristocrats could elevate themselves to positions of authority.

So, unsurprisingly, some of the leading astronomers and scientists of the day were Catholic clergy, including Christopher Clavius, Francesco Maria Grimaldi, Giovanni Battista Zupi, Pierre Gassendi, Charles Malapert, Orazio Grassi and Christoph Grienberger. Jesuit astronomers alone have no less than 34 craters and other features on the Moon named after them, thanks to their prominence in the field in this period. Even those who did not specialise in the field had a sound knowledge of it and, often, a keen interest in its developments. The Chief Inquisitor, Cardinal Robert Bellarmine, was a theologian, but he had taught on astronomy and cosmology at the University of Louvain. Cardinal Maffeo Barberini, who as Pope Urban VIII was to become Galileo’s nemesis, was first his admirer on account of his great interest in astronomy. The idea the opponents of Galileo belonged to a coterie of scientific illiterates is simply wrong.

So is the idea they ignored the science completely and worked purely from dogmatic Biblical literalism. To begin with, the Catholic Church (then, and now) was not rigidly Biblical-literalist – that is a largely Protestant, very recent, and mostly American theological quirk. Medieval and Early Modern interpretation of the Bible relied on a traditional fourfold system of exegesis:

• Literal Sense: The straightforward, historical meaning intended by the human author.
• Allegorical Sense: The symbolic meaning, often connecting Old Testament figures/events to Christ.
• Moral/Tropological Sense: The ethical teachings and how to live a good life.
• Anagogical/Eschatological Sense: The spiritual or mystical meaning pointing to heavenly realities or the end times.

Any given text could have one, two, three or even all four of these interpretive senses. And they did not necessarily have to be read literally at all.

Of course, many texts were interpreted and understood literally, but this was not required. It was not even required when the text seemed to conflict with what we would call “science” and they called natural philosophy. This is because they also worked with the Two Books Doctrine. This was based on the idea that creation could be understood via two metaphorical books; the Book of God (Scripture, Patristic writings, conciliar canons, Papal decrees, etc.) and the Book of Nature (analysis of the natural world via observation and reason). It was thought both books ultimately came from God, so they could not contradict each other, which meant that if one seemed to do so, it was because it was being misinterpreted by men. This meant a reasoned argument about nature based on observation may be mistaken if it seemed, for example, to contradict Scripture. But, importantly, it also meant that it could be that man has misinterpreted Scripture and this needed to be brought into line with an understanding of nature.

This was a standard idea in medieval theology and was expressed in various forms by Bernard of Clairvaux, Hugh of St. Victor, Bonaventure, Thomas Aquinas, Thomas of Chobham and many others. That the Two Books could and should illuminate each other was certainly well-understood by Galileo, who invoked the concept himself a number of times. For example:

To prohibit the entire science [of astronomy] would be no different than to reject hundreds of statements from the Holy Writ, which teach us how the glory and the greatness of the supreme God are marvellously seen in all of His works and by divine grace are read in the open book of the heavens. (“Letter to the Grand Duchess Christina” 4.2.3,The Essential Galileo, Maurice Finocchiaro (ed.), Hackett, 2009, p. 128)

The clearest example of where Scripture came to be re-interpreted in light of what we would call science concerned the understanding of the shape of the Earth. A few early Christian writers interpreted Biblical references to the Earth literally and held that it was flat. But most were literate in Greek natural philosophy and argued this reading conflicted with observation and reason. They prevailed, and the texts in question came to be read allegorically (see “The Great Myths 1: The Medieval Flat Earth“). This example of science reinterpreting the Bible was also well known and was invoked many times in discussions about Galileo in the two centuries after his death as an option for the rehabilitation of his ideas – which ultimately happened (see “Did the Pope Apologise to Galileo”).

So it was not the case that Galileo’s opponents were ignorant of science and nor was it required that they stick rigidly to a literal interpretation of the Bible in relation to the question of heliocentrism. The passages in the Bible that even touched on the matter were very few (basically, Joshua 10:12-13, Psalms 93:1 and 104:5, 1 Chronicles 16:30, Ecclesiastes 1:5, and Psalm 96:10) and they were not central to any major dogma, so it is also not as though there would have been any other great obstacle to interpreting them figuratively.

The reason most theologians accepted their traditionally literal interpretation was not in spite of science but because of it. As detailed above, the consensus of science was firmly against heliocentrism in the early seventeenth century and had been so for about one thousand years by that stage; which meant that, for the majority of scientists and theologians in 1616 or 1633, the Book of God and the Book of Nature seemed to be in full agreement.

Some try to argue that, even if this was so, it is somehow irrelevant to the Galileo Affair. The Church’s accusations against Galileo were based on theology, they argue, not science. They claim he was accused of contradicting Scripture, not of supporting a scientific view rejected by the consensus of scientists. But this is not correct. The 1616 consultants’ report on heliocentrism to the Inquisition and the 1633 condemnation of Galileo both refer directly to the scientific consensus. On February 24 1616 the Inquisition received an assessment on heliocentrism that was used to ban some books and place restrictions on future discussions (see more on this below). Signed by ten theologians and academics, it came to this conclusion:

(1) The Sun is the center of the world and completely devoid of local motion.
Assessment: All said that this proposition is foolish and absurd in philosophy; and formally heretical since it explicitly contradicts in many places the sense of Holy Scripture, according to the literal meaning of the words and according to the common interpretation and understanding of the Holy Fathers and the doctors of theology.
(2) The Earth is not the center of the world, nor motionless, but it moves as a whole and also with diurnal motion.
Assessment: All said that this proposition receives the same judgment in philosophy and that in regard to theological truth it is at least erroneous in faith.

The term “foolish and absurd in philosophy” refers to natural philosophy, or what we call “science”, so both propositions are given the same assessment: they are scientifically wrong and contradict Scripture. Thus the Two Books doctrine is upheld easily – they are completely in agreement. There are two points to note here. First, the scientific and the scriptural assessments are distinct from each other. The semi-colon after “absurd in philosophy” is significant: it means the assessment is not that the propositions are absurd in philosophy because they contradict the common interpretation of Scripture, but as well as this. On this point, see Maurice Finocchiaro’s detailed endnote (The Galileo Affair: A Documentary History, University of California Press, 1989, p. 146, n. 35, p. 344) and Christopher Graney’s excellent online article “The Inquisition on Copernicus, February 24, 1616: A Little Story About Punctuation” (2016). Second, the scientific consensus is given the primary position and so is mentioned before the Scriptural interpretation.

We can also see this in the condemnation of Galileo at the end of his 1633 trial, where the ruling referred directly to the consultants’ report from 1616:

[T]he Assessor Theologians assessed the two propositions of the Sun’s stability and the Earth’s motion as follows:

That the Sun is the center of the world and motionless is a proposition which is philosophically absurd and false, and formally heretical, for being explicitly contrary to Holy Scripture;

That the Earth is neither the center of the world nor motionless but moves even with diurnal motion is philosophically equally absurd and false, and theologically at least erroneous in the Faith. (Finocchiaro, Documentary History, p. 288)

Once again, the scientific consensus and the scriptural interpretations are given as distinct but mutually supportive and it is the science that is given primary position. This shows that this scientific consensus was not only entirely relevant to the whole affair but actually central to it. The theological position was based, in large part, on the agreement between the “Two Books” of science and scriptures, therefore not only were the churchmen involved in the Galileo Affair scientifically literate, this literacy was central to their theological position.

The idea that the churchmen who persecuted Galileo refused to look through his telescope “to see his evidence with their own eyes” etc. is also a myth. It is very loosely based on a few pieces of evidence, none of which add up to what the myth claims. According to a letter to Galileo, it is said that Cesare Cremonini – Professor of Aristotelian Philosophy at the University of Padua and a friend of Galileo’s – responded to reports of findings via observations using the newly-invented telescope saying “I do not wish to approve of claims about which I do not have any knowledge, and about things which I have not seen” and adding “to observe through those glasses gives me a headache. Enough! I do not want to hear anything more about this.” This is a clear expression of conservatism by a philosopher, but to a certain extent his scepticism had validity. Telescopes were a very recent invention and at this stage it was not clear how much of what they observed were actually artefacts of the instrument. As it turned out, some of these early observations drew conclusions from things which genuinely were distortions by the instrument. Throughout the seventeenth century astronomers based arguments on their observations of the “size of the stars”, when what they were measuring were Airy discs; distortions caused by the optics of early telescope lenses. Cremonini’s headache comment could also indicate that he actually had, in fact, looked through a telescope. All this aside, Cremonini was an academic, not a churchman.

The other relevant evidence here is a quip by Galileo on hearing of the death of Guilio Libri, Professor of Aristotelian Philosophy at Pisa and an academic enemy of Galileo’s. He died in 1612, not long after news of Galileo’s early telescopic discoveries became known. In a letter to Mark Welser, Galileo joked of Libri “never having wanted to see [the moons of Jupiter] on Earth, perhaps he’ll see them on the way to heaven!”

The only churchman who expressed caution about telescopic observations was the Jesuit scientist and professor at the Collegium Romanum, Christopher Clavius. On reading of Galileo’s observations of craters and mountains on the Moon in his book Siderius Nuncius (“The Starry Messenger”) in 1610, Clavius was initially sceptical – again because telescopes were still an uncertain novelty. But rather than just dismissing the new evidence, Clavius did what a scientist should do: he tested it. At the invitation of Cardinal Bellarmine, Clavius instructed a committee of Jesuit astronomers from the Collegium Romanum to construct a telescope and see if they could confirm Galileo’s observations. The Jesuit scientists Christoph Grienberger, Paolo Lembo and Odo van Malecote did this and reported back that the observations were correct. Clavius accepted this verdict, though he later expressed some continued doubt about the idea of mountains on the Moon.

And far from rejecting them, the Church celebrated Galileo’s discoveries. On March 29 1611 Galileo arrived in Rome from Florence and met first with the great patron of science and art, Cardinal Francesco del Monte. The Cardinal had helped Galileo secure his first lectureships in Pisa and then Padua and he listened to Galileo’s account of his astronomical discoveries with great interest. The next day Galileo went to the Collegium Romanum where he met Clavius and two of the scientists who had confirmed his observations: Grienberger and Maelcote, who he noted in a letter were working on further observations of the moons of Jupiter “to find their periods of revolution”. Far from rejecting his findings as heretical, these churchmen were working to add to them. On April 2 Galileo visited the powerful Cardinal Maffeo Barberini – later to become Pope Urban VIII – who afterward wrote to pledge his assistance to Galileo in any way within his power. Then he visited Cardinal Ottavio Bandini, who invited him to give a demonstration of his telescope in his private garden for members of his household and Roman high society. Finally, Galileo was granted an audience with Pope Paul V at the Vatican and later wrote about the way the Pope had greatly honoured him during the meeting.

On May 13 the Jesuits and scientists of the Collegium Romanum awarded Galileo the equivalent of an honorary degree, with Maelcote delivering a glowing address at a banquet in his honour praising his discoveries and including a description of the surface of the Moon. Out of deference to the continued doubts of Clavius on this matter, however, he left the question of whether the features seen via telescopes were actual mountains and craters or attributed to “the uneven density and rarity of the lunar body”, as some sceptics still believed. 

So the idea that the churchmen of the time were scientifically illiterate, rejected science and refused even to consider new evidence is all complete nonsense and exactly the opposite of the historical facts.

“The Church regarded heliocentrism as heresy and persecuted anyone who argued for it.”

“The dogmatic rejection of heliocentrism meant anyone who proposed it was persecuted by the Inquisition and in danger of being burned at the stake as a heretic.“

(i) Reaction to Copernicus

It should already be clear that the popular idea that the Catholic Church automatically regarded any acceptance of heliocentrism as heresy and persecuted anyone who held this view is wrong. Obviously there could not have been an ongoing, open and vigorous debate about it and its competitors among astronomers and natural philosophers if this debate was impossible across half of Europe. Indeed, if this were the case then this article would not be about the Galileo Affair, but rather about the Copernicus Affair. After all, Galileo did not invent the heliocentric model he defended.

The mythological version of the story has an explanation, of sorts, for why it was Galileo who was persecuted and not Copernicus. In this telling, Copernicus kept his thesis a secret, only revealing it to his closest friends, and then published his De Revolutionibus on his deathbed, thus escaping the clutches of the Inquisition. But this is complete nonsense.

As detailed elsewhere (see “The Great Myths 6: Copernicus’ Deathbed Publication”), Copernicus did not keep his ideas a secret and began circulating them for discussion decades before he published his final book. Around 1512 he also wrote an eight chapter summary of his theory – the so called Commentariolus – which then circulated in unpublished form among interested astronomers and mathematicians. It was noted by a number of leading scholars, and was read by the Humanist scholar Erasmus of Rotterdam, the Cracow cartographer and historian Bernard Wapowski, and is also found in the library catalogue of Matthew of Miechów in 1514. Further and wider publicity for Copernicus’ thesis came three years before De Revolutionibus with the publication of the Narratio prima by Georg Joachim Rheticus in 1540 (full title: De libris revolutionum Copernici narratio prima), which gave a further summary of Copernicus’ forthcoming work. The idea that Copernicus’ thesis was “kept secret” is ludicrous.

More significantly, the Commentariolus was circulated by Copernicus’ friend and patron  Bishop Tiedemann Giese of Culm, sparked the interest of Cardinal Nikolaus von Schönberg and attracted the enthusiastic attention of Pope Clement VII. The Pope requested that Cardinal von Schönberg’s secretary, Johann Albrecht Widmanstadt, give him a private lecture on the theory. So in August 1533, Widmanstadt stood before the pontiff in the Vatican gardens and explained Copernicus’ thesis to an interested audience that also included leading members of the Curia and Papal court, including Cardinal Franciotto Orsini, Cardinal Giovanni Salviati, the Bishop of Viterbo Giampietro Grassi and the papal physician Matteo Corte. The Pope was fascinated by the theory and rewarded Widmanstadt with a precious manuscript of Alexander of Aphrodisias’s De sensu et sensibili, with Widmanstadt proudly inscribing the circumstances in which he received this gift in its front pages. So much for Copernicus keeping his theory a secret from a persecuting Catholic Church.

(It should also be noted that Copernicus died of a brain haemorrhage suffered in late 1542 and spent several months in a coma before dying on May 24, 1453. This makes the nineteenth century idea that he somehow planned the timing of the publication of De Revolutionibus from his deathbed as a cunning ruse to escape the Inquisition doubly absurd. Yet it continues to be repeated to this day.)

The reception of De Revolutionibus also shows there was no kneejerk rejection of its thesis by the Church. The book was, like its precursors, received with interest. Its cosmology was, as already noted, not found to be convincing by most scholars, but its usefulness as a calculating device for astronomical observers was recognised and this meant the book stayed in circulation and avoided the fate of other attempts at a heliocentric model, such as the highly complicated and less mathematically useful Homocentrica, which was published by Girolamo Fracastoro in 1538 and sank without much trace.

Owen Gingerich’s The Book Nobody Read: Chasing the Revolutions of Nicolaus Copernicus (Walker, 2004) debunks Arthur Koestler’s claim that De Revolutionibus was not banned or condemned because it was largely ignored. Gingerich has tracked down the surviving copies of Copernicus’ book to show how it was extensively used. Interestingly, he shows that the sections on the cosmology were clearly less used than the sections on calculation of the positions of heavenly bodies; which were heavily thumbed, stained and annotated. Copernicus’ book was read, it was just that the part that interests modern writers most was regarded as unconvincing and so not useful by astronomers of the time. Significantly, Erasmus Reinhold used Copernicus’ calculations to develop the Prutenic Tables in 1551, which were used as a basis for the calendar reform instituted in 1582 by Pope Gregory XIII.

Before 1616, the objections to Copernicus’ thesis were primarily scientific, not theological, and actual religious arguments against it in this period are few and far between. The most clear-cut example was an appendix by the Dominican theologian and astronomer Giovanni Maria Tolosani to his On the Truth of Sacred Scripture (1544), in which he made both scientific and theological arguments against Copernicus. But this work was never published, so it is not exactly strong evidence of a Church backlash against Copernicus’ book.

This general theological ambivalence toward Copernicanism continued into the early seventeenth century. In 1613 Galileo sought and received an imprimatur from the Roman Inquisition to publish his booklet Letters on Sunspots. It was normal across Early Modern Europe for any author or publisher to seek an authority’s permission to publish so as to guard against post-publication censure in a censorious age. In this case, the Inquisition did order a few changes to some of Galileo’s references to Scripture, but otherwise approved the book for publication.

This imprimatur is significant because in this work, Galileo effectively declares himself a Copernican and uses several arguments based on Copernicus’ model. The Inquisition’s censors were sensitive and attentive enough to insist on the removal of a quotation from Matthew 11:12 from the book’s opening, but did not bat an eyelid at the sections where Galileo promotes heliocentrism. They simply did not care.

So what changed?

Clearly something did change, because just three years later, in 1616, the Inquisition’s assessors made the rulings on heliocentrism quoted above and the Congregation of the Index placed several books on the subject on the Index Librorum Prohibitorum. Understanding of what caused this change and what the change meant is essential to understanding the Galileo Affair.

(ii) The Collision of Theology with Cosmology

The origins of the eventual theological rulings on heliocentrism by the Catholic Church lie in a key dispute between the Church and Protestant reformers regarding the interpretation of the Bible. Luther argued against the fourfold exegesis noted above and preferred a “literal-historical” approach to interpretation, accessing a plain, historical meaning as intended by the Holy Spirit. He presented a doctrine of inherent Biblical perspicuity, asserting that the Bible is clear enough to be apprehended by ordinary believers without the necessity of interpretation by Church authorities.

Not only did Catholic scholars disagree about this general principle, they also noted that this would lead to a wild variety of conflicting interpretations leading inevitably to the fragmentation of Christendom into a myriad of competing sects. The formal response to the Protestant view came via the Council of Trent (1545-1563); particularly the decrees following its Fourth Session in 1546. The second of these included the following ruling:

Furthermore, to check unbridled spirits, [the Council] decrees that no one relying on his own judgment shall, in matters of faith and morals (in rebus fidei et morum) pertaining to the edification of Christian doctrine, distorting the Holy Scriptures in accordance with his own conceptions, presume to interpret them contrary to that sense which holy mother Church, to whom it belongs to judge of their true sense and interpretation, has held and holds, or even contrary to the unanimous teaching of the Fathers, even though such interpretations should never at any time be published. Those who act contrary to this shall be made known by the ordinaries and punished in accordance with the penalties prescribed by the law.

(“Fourth Session of the Council of Trent – Decree Concerning the Canonical Scriptures”)

This was a direct counter to Luther and the Reformers’ doctrine of Biblical perspicuity and effectively made the interpretation of Scripture the sole preserve of those trained in the interpretations of the Church, the Patristic writers (“the Fathers”) and various ecumenical councils and learned doctors of theology. But the key term here is the reference to how this pertains “in matters of faith and morals” (in rebus fidei et morum). As Richard J. Blackwell notes in his Galileo, Bellarmine and the Bible (University of Notre Dame Press, 1991, pp. 12-13), the Latin word “mores” here encompasses far more than “morals” and covered a wide range of practical matters including everything from the canon of Scripture to Church councils, papal elections, the administration of sacraments and a great deal more besides.

But as any lawyer knows, once legal parameters are established the debate begins regarding what does or does not fall within them. The Spanish Dominican theologian Melchior Cano began the process of determining what did or did not fall under the rubric of “in rebus fidei et morum” in his posthumously published De locis theologicis (1563). Cano had been a theological adviser to the Council of Trent and so his analysis most likely reflects the thinking that lay behind the 1546 decree. It also makes it clear that determining if something did qualify as relating to “matters of faith and morals” was far from straightforward, with Cano giving eight rules to aid those seeking to interpret this edict (see Blackwell, pp. 17-18).

Unsurprisingly, it was also not long before the question of whether and how matters of natural philosophy – including what we call “science” – fell under “matters of faith and morals”. The Jesuit theologian Benito Pereyra laid out the parameters here in his Commentariorum et disputationum in Genesim tomi quattuor (1591–1599), giving four rules to help reconcile the “Book of Nature” and the “Book of God” in light of the Tridentine decree of 1546 (see Blackwell, pp. 21-22) which concluded, in keeping with the Two Books Doctrine, that “since every truth agrees with every other truth, the truth of Sacred Scripture cannot be contrary to the true arguments and evidence of the human sciences.”

In previous centuries the reconciliation of Moses, “the Fathers” and “the saints”, as well as the Councils and doctors of the Church, with the findings of human sciences and inquiry was perhaps less complicated than it became in the 150 years before the Galileo Affair. The discovery of the New World, the appearance of “new stars” (the supernovae of 1572 and 1604) and the beginnings of the true empirical scientific method generally had increasingly shown, as wise as the Patriarchs and Fathers had been, there was a great deal about the natural world they had not known or had been wrong about. So the question of how or even whether natural sciences like astronomy should be constrained by the traditional interpretations of Scripture became a subject for discussion and contemplation by the learned.

This clearly included Galileo. Some modern polemicists seem to imagine Galileo was a religious sceptic or, at least, someone who merely paid lip service to religion out of social convention or reluctant acceptance of the Church’s power. In fact, the evidence is very clear that Galileo was a devout Catholic and a genuine believer. Olaf Pedersen’s detailed and careful analysis of the evidence in “Galileo’s Religion”, The Galileo Affair: A Meeting of Faith and Science: Proceedings of the Cracow Conference, May 24-27, 1984, Citta del Vaticano: Specola Vaticana, 1985, edited by Coyne, G.V., pp.75-102) shows this beyond reasonable doubt. And his writings on the issue of how heliocentrism can be reconciled with Scripture are also very obviously the work of someone for whom this was a personal issue, not some academic abstraction. Galileo’s Letter to Castelli (1613, see below) and his longer Letter to the Grand Duchess Christina (1615) tackle this subject, as do other private notes and writings. The two Letters, in particular, show familiarity with the theological discussions referred to above, particularly Pereyra’s commentaries.

Galileo was determined that his faith and his scientific convictions should not be in conflict. Unfortunately these two previously separate and very distinct questions – the scientific one regarding which cosmological model reflected reality and the theological one about the interpretation of Scripture – were converging, and were about to collide on the morning of 11 December, 1613.

That morning the rulers of Tuscany, the Grand Duke Cosimo de Medici and his wife Maria Maddalena, held a reception and Galileo’s student and supporter, Benedetto Castelli, was among the guests. This was a meal that was far more informal than the highly stylised and ritualised grand banquets such nobles gave, and an opportunity for music, banter and witty and learned conversation. So during the meal the dowager Archduchess Christina, Cosimo’s mother, had some questions for Castelli about the moons of Jupiter and their motions, which he answered. Afterwards, as he was leaving, Castelli was called back to answer further queries, seemingly spurred on by the scepticism of another guest, Cosimo Boscaglia, professor of philosophy at the University of Pisa. According to a letter Castelli wrote to Galileo three days later (see Finocchiaro, Documentary History, pp.47-8), the older lady “began to argue against me by means of the Holy Scripture” and so Castelli responded by “[playing] the theologian with such finesse and authority that you would have been especially pleased to hear.” The Archduchess responded, though Castelli thought “she was doing it to hear me” and added “Mr Boscaglia remained silent.”

Ten days after Castelli wrote describing this discussion, Galileo replied (21 December, Finocchiaro, Documentary History, pp.49-54) with a detailed summary of his theological position, arguing:

I should believe that the authority of the Holy Writ has merely the aim of persuading men of those article and propositions which are necessary for their salvation …. However, I do not think it necessary to believe that the same God who has furnished us with senses, language, and intellect would want to bypass their use and give us by other means the information we can obtain with them. (Letter to Castelli)

This letter was copied and circulated by Castelli and then by others, as was a common practice at the time. As a result, it became widely known and read by a range of scholars and aroused considerable interest and discussion over the following two years. Not all of its readers were friends and admirers of Galileo. They included a group of Galileo’s academic rivals and opponents who were dubbed (not by Galileo, but by his friend the painter Lodovico Cigoli) as “the Pigeon League” (Lega dei Colombi). This nickname derived from the clique’s perceived leader, the Florentine Aristotelian philosopher Lodovico delle Colombe, whose surname can mean both “dove” and “pigeon” in Latin and Italian. The group also included the Dominican preacher Tommaso Caccini and his fellow Dominican and lecturer in history Niccolò Lorini. Florence’s archbishop Alessandro Marzi Medici and Cosimo Boscaglia, the sceptical guest at the Tuscan Duke’s reception, were also associated with this group of scholars. It seems that this group saw the Letter to Castelli as an opportunity to attack Galileo’s religious orthodoxy.

On December 20 1614 Caccini preached a fiery sermon in Santa Maria Novella, Florence, condemning Copernicanism; specifically targeting Galileo and taking Acts 1:11 as his text: “Men of Galilee, why stand there looking into the sky?” (in Latin “Viri Galilaei, quid statis aspicientes in caelum?”, with a pun on Galileo’s name). On 7 February 1615, Lorini followed this by formally denouncing people he called the “Galileists” (though not Galileo personally) to the Inquisition in Rome, along with a copy of the Letter to Castelli as evidence of heresy.

But “the Pigeon League” was to be disappointed. A Consultant’s report on the Letter to Castelli made to the Inquisition in March 1615 identified a few minor points of concern, but ultimately concluded there was no real issue with the document:

For the rest [of the Letter], though it sometimes uses improper words, it does not diverge from the pathways of Catholic expression. (Finocchiaro, Documentary History, p. 136.)

This was not the conclusion Galileo’s enemies wanted, so Caccini tried to press the issue by – unusually – requesting to appear before the Inquisition personally to argue the point. On 19 March 1615 he gave a deposition where he detailed his views on Galileo’s Copernicanism and making other accusations casting suspicion on his orthodoxy. He was asked for witnesses who could corroborate his claims and he said a fellow Dominican, Ferdinando Ximenes, and a young Florentine noble, Gianozzo Attavanti, could do so. The Florentine Inquisition was asked to question these two men and eventually got around to doing so in November 1615. Their depositions were forwarded to Rome. There does not seem to have been much urgency around these proceedings and correspondence by friends of Galileo from Rome advised him that if Galileo were to speak purely “as a professor of mathematics”, senior figures like Cardinal Maffeo Barberini and Cardinal Bellarmine were unlikely to have a problem with him (see William R. Shea and Mariano Artigas, Galileo in Rome, Oxford University Press, 2003, pp.64-7 on the correspondence here and the conversations in Rome they report).

There is a good chance that this is how things could easily have been left, but for a new theological bombshell dropped at around this point by a hitherto obscure Carmelite priest, Paolo Antonio Foscarini. He had been a lecturer in philosophy in Messina before taking up the office of Provincial of the Carmelite Order in Calabria. Just as Galileo was an astronomer with an interest in theology, Foscarini was a theologian with an interest in astronomy; one who later described himself as “an affectionate admirer” of Galileo. Sometime before March 1615 he wrote a pamphlet titled Lettera del R.P.M. Paolo Antonio Foscarini carmelitano. Sopra l’opinione de’ Pittagorici, e del Copernico. Della mobilità della terra, e stabilità del sole, e del nuovo pittagorico sistema del mondo (“On the opinion of the Pythagoreans and Copernicus concerning the motion of the Earth, the stability of the Sun, and the new Pythagorean system of the world”) which he had printed in Naples on his way to preach in Rome. This booklet argued very much along the same lines as Galileo’s Letter to Castelli: that if Copernicanism could be proven, there were ways to harmonise it with the Bible.

Not long after his arrival in Rome Foscarini’s Lettera attracted the attention of the Inquisition and a votum or censor’s note was drafted by an anonymous theologian‑consultant and given to the members of the Congregation, highlighting theologically problematic aspects of the work. On March 21 1615 Galileo’s friend Giovanni Ciampoli, a priest with connections to the Roman Curia, wrote to Galileo to warn that Foscarini’s Lettera had attracted adverse attention. Ciampoli later met with Foscarini and seems to have warned him as well, which led to Foscarini writing a defence of his work which he sent directly to the Chief Inquisitor, Cardinal Robert Bellarmine, effectively asking Bellarmine to intervene and rule on the orthodoxy of Foscarini’s arguments.

As noted above, Bellarmine replied in his “Letter to Foscarini” of April 12, 1615, ruling that if heliocentrism were demonstrated then some Scriptural texts would need to be reinterpreted, though adding “but I will not believe that there is such a demonstration, until it is shown me.” Significantly, this left the door open to a future proof that heliocentrism was true. However, Bellarmine also ruled that “in case of doubt one must not abandon the Holy Scripture as interpreted by the Holy Fathers” and observed:

Consider now, with your sense of prudence, whether the church can tolerate giving Scripture a meaning contrary to the Holy Fathers and to all the Greek and Latin commentators. Nor can one answer that this is not a matter of faith, since it is not a matter of faith “as regards the topic”, it is a matter of faith “as regards the speaker”.

This effectively brought the heavy weight of the Church’s chief theologian down on one side of the question regarding whether an astronomical question fell under the Council of Trent’s rubric of “in rebus fidei et morum”. Here Bellarmine is saying that the traditional authorities do indeed apply here, not so much because of what they say or the extent of their human knowledge, but because of who they are: divinely inspired teachers and guides for the ages.

As already mentioned, in November 1615 the Inquisition in Florence investigated Caccini’s more serious claims about Galileo’s orthodoxy and, on questioning Ximenes and Attavanti, appear to have found the claims insufficiently established. So, with Bellarmine having ruled on Foscarini’s arguments regarding heliocentrism and the interpretation of Scripture, the Roman Inquisition turned to the more significant issue of the theological standing of heliocentrism itself. On February 24 1616, the Inquisition received the report of 11 scholars asked to theologically assess two propositions: (i) that the Sun was “the centre of the world” and (ii) the Earth “moves as a whole and also with a diurnal motion”. On the first proposition, the central position of the Sun, the assessors ruled:

All [assessors] said that this proposition is foolish and absurd in philosophy; and formally heretical since it explicitly contradicts in many places the sense of Holy Scripture, according to the literal meaning of the words and according to the common interpretation and understanding of the Holy Fathers and the doctors of theology.

As already discussed above, here “philosophy” means “natural philosophy” or what we today would call “science”, so this finding not only refers directly to the scientific consensus, but also places this first in its assessment. As Finocchiaro notes and as Graney discusses in detail, the finding that this proposition “contradicts in many places Holy Scripture” is at least in part dependent on the scientific consensus. The hand of Bellarmine is very clear here. As in his argument to Foscarini, it is the doubt about heliocentrism agreed by the scientists that forms the basis for the ruling that “the common interpretation and understanding of the Holy Fathers and the doctors of theology” should be upheld. On the second proposition, the movement of the Earth, the assessors made a different finding:

All said that this proposition receives the same judgment in philosophy and that in regard to theological truth it is at least erroneous in faith.

Here the assessors rule that the second proposition has the lesser theological status of “erroneous in faith” rather than “formally heretical”. To an extent, this is a purely technical distinction, though these theologians took such distinctions very seriously. The first proposition is rejected by science and directly contradicts the traditional interpretations of Scripture, so it entails a rejection of the Church’s teaching authority. Whereas the second, also rejected by science, is not unambiguously in conflict with any defined teaching, but is close enough to be ruled an error. Thomas F Mayer discusses these technical distinctions in detail – see Mayer, ed., The Trial of Galileo, 1612–1633: A Documentary Edition, (University of Toronto Press, 2012, pp. 15-25) and also Finocchiaro, Retrying Galileo, 1633–1992, (University of California Press, 2005, pp. 15-22 and 35-40).

It should also be noted that while this Inquisitorial assessment found at least one of the propositions to be heretical and both to be theologically erroneous, this did not – contrary to many assertions in pop history accounts – make this a dogma of the Catholic Church. That would require a ruling by either the Pope or an Ecumenical Council. The opinion of Bellarmine and the ruling of the Inquisition carried some considerable authoritative weight, but this was not now doctrine. That meant, significantly, that this ruling was reversible and could be overruled; as it subsequently was.

As a result of this assessment, on March 5 1616 the Congregation of the Index issued a decree banning a number of books promoting “the false Pythagorean doctrine …. that the Earth moves and the Sun is motionless” banning Foscarini’s Lettera on the grounds that it “tried to show that the above-mentioned doctrine …. is consonant with the truth and does not contradict Holy Scripture” (Finocchiaro, Documentary History, p. 149). It is often claimed this same decree banned Copernicus’ De Revolutionibus, but in fact it did not. Instead, it says that this book, along with Diego de Zúñiga’s In Job commentaria, should be “suspended until corrected”. It was “uncorrected” copies of these works that remained on the Index Prohibitorum until 1835. Copies that had “corrections” of a few passages and sentences written or pasted into them were allowed. In the case of Copernicus’ book, these corrections were released in 1620 and many devout astronomers, including Galileo, dutifully added them to their copies (though this was largely ignored outside Italy). So the corrected books mentioned allowed the heliocentric thesis to be used as a calculating device and it continued, with a few caveats, to be discussed as a hypothesis or calculating device, though the decree did rule that “all other books that teach the same [as Foscarini, on Scriptural reinterpretation] be likewise prohibited.”

So the issues were with (i) the idea that heliocentrism was fact and (ii) that it was compatible with Scripture. Noticeably absent from this decree is any mention of Galileo or any of his works. This is because a week earlier, Galileo had been dealt with privately. On February 25 the minutes of a meeting of the Inquisition noted Pope Paul V had ordered Galileo be summoned before Cardinal Bellarmine and commanded to “abandon these opinions [on heliocentrism]” (Finocchiaro, Documentary History, p. 147). A note to the Inquisition dated to the next day, February 26, detailed the order that was given by Bellarmine that day. Then on March 3 it was reported to the Inquisition that the order had been given and “Galileo Galilei had acquiesced” (Finocchiaro, Documentary History, p. 148).

The order given to Galileo on February 26 would later be the pivotal point in his trial in 1633. Crucially, he had been commanded “not to hold, teach or defend [heliocentrism] in any way whatever, either orally or in writing” and it was recorded that “the same Galileo acquiesced in this injunction and promised to obey.” (Finocchiaro, Documentary History, p. 147-8)

There are several important things to note here. Firstly, the personal injunction given to Galileo was fairly unequivocal and definitely restricted him far more than the general decree of the Index restrained discussion of heliocentrism for everyone else. Despite this, later events would prove that he came to remember or understand it as giving him more leeway in this regard than it did. Secondly, the fact this stricter personal injunction was given in private while he and his works were not mentioned by the public decree issued the following week is also significant.

It appears this private injunction was due, at least in part, to a reasonable level of respect that Galileo had among intellectuals in Rome, including many senior churchmen. That said, the order to be silent on the matter was also a form of academic gatekeeping. Respected as an astronomer though he may have been, he was not a theologian. In the hierarchy of academic disciplines in this period, he was a mere mathematicus; strictly speaking on the same level as a mathematics tutor and so far below the theologians who sat at the very top of the scholarly hierarchy. In a period in which hierarchy and authority mattered a great deal, this was important. So to a large degree this order was the theologians putting an upstart in his place for dabbling in their field.

But there also seems to be an awareness of the context in which the whole issue had arisen. Galileo’s theological dabbling had made him a target of “the Pigeon League” in a period in which theology was not an obscure philosophical byway, but a potential political minefield. Galileo had a reputation for being obstinately argumentative. At university in Pisa in the 1580s his nickname had been “the Wrangler” on account of his tendency for trying to win any debate and the older Galileo also never backed down willingly. So it would seem that the personal injunction was at least partially to save him from himself and deprive his academic enemies of a potential target in the future.

This quickly proved necessary. In the months after Galileo was given his personal injunction it seems “the Pigeon League” spread the rumour that he has been accused of heresy, had abjured, and had been given penances in punishment. So on May 26 1616 Cardinal Bellarmine issued a certificate to Galileo making it clear that this had not happened. It said he had simply “been notified of the declaration made by the Holy Father and published by the Sacred Congregation of the Index” that “the doctrine attributed to Copernicus …. could not be defended or held” (Finocchiaro, Documentary History, p. 153).

And that, it seemed, was the end of the matter. At least for a while.

So it can be seen that the pop history idea the Church automatically condemned heliocentrism is highly misleading. Copernicus’s ideas were widely discussed, read, and even welcomed by church figures, and his book was used mainly for its calculations rather than accepted cosmology, for wholly scientific reasons. The real conflict emerged when theological concerns about how Scripture should be interpreted collided with astronomy, leading to the 1616 general ruling against heliocentrism being presented as fact, and Galileo’s stricter private warning not to teach it in any way at all. And it was this last element that led to his later trial in 1633.

“Galileo was hauled before the Inquisition where he bravely defended his scientific proofs.”

Galileo defended his science before the Inquisition and only recanted because he was threatened with torture and ran the risk of being burned at the stake.

Galileo’s trial forms the climax of the Galileo Affair and it the mythological version of the story it is a simple matter. Galileo was summoned to appear before the Inquisition – in some versions he is arrested and brought by force – and charged with heresy. He then defended his science with clear and detailed reference to his evidence and proofs of heliocentrism, but he is threatened with torture or even execution and so, reluctantly, recants, but he mutters “Eppur si muove!” (“And yet it moves!”) immediately afterwards, brave and defiant to the end. Of course, the historical reality is entirely different.

(i) The Rocky Road to Publication

Things could well have stayed as they were left in May 1616, after which, for several years, Galileo obeyed the personal injunction and avoided discussion of Copernicanism. But circumstances changed when, on 6 August 1623, Cardinal Maffeo Vincenzo Barberini was elected as Pope Urban VIII. Barberini was born into a Florentine noble family and raised in Rome by his uncle. He was well-educated, with a law degree from Galileo’s alma mater, the University of Pisa, and quickly rose in the ranks of the Church. As a Cardinal he had been well-disposed to Galileo and was a patron of the arts and sciences, taking an interest in Galileo’s astronomy and other scientific work. In 1616 he wrote to Galileo admiringly about his “Letters on Sunspots” and in 1620 he sent a number of poems he had written in praise of Galileo’s achievements with an enthusiastic letter:

The esteem which I always entertain for yourself and your great merits has given occasion to the enclosed verses. If not worthy of you, they will serve at any rate as a proof of my affection, while I purpose to add lustre to my poetry by your renowned name. (Karl von Gebler, Galileo Galilei and the Roman Curia, p. 111)

As Pope Urban VIII, he was the archetype of a Renaissance Pope: grand, proud, ostentatious and politically active or even aggressive, but also urbane, sophisticated, educated and cultured. His admiration for Galileo presented a great opportunity for the mere mathematicus to advance his station, increase his prestige and – most importantly – gain political protection. Much modern analysis of the Galileo Affair sees Galileo through an anachronistically erroneous lens: as though he was a modern academic with the freedoms and motivations of a current university professor or scholar. But the freedom of ideas that exists for scholars today did not exist in Galileo’s time. Scholars, then as now, needed financial support. But scholars like Galileo also needed patrons for protection in a period when ideas could be dangerous.

Probably the best account of this as a way to better understand the politics of the Galileo Affair is Mario Biagioli, Galileo, Courtier: the Practice of Science in the Culture of Absolutism (University of Chicago Press, 1993). As Biagioli details, the role of a scholar like Galileo in the courts of Italy was to raise his patrons’ reputation by displays of scholarship and attention for remarkable new ideas and arguments. What the scholar got in return was exposure, financial support and, if required, protection. This was the nature of the patron/courtier-client relationship across Europe, and as Ada Palmer explains in entertaining detail in Inventing the Renaissance: Myths of a Golden Age (Bloomsbury, 2020), the protection a patron provided could literally let a client get away with murder or even, in one case, a signed demonic contract by which an apprentice planned to sell his soul to sleep with his masters’ wife (see Palmer, pp. 199-218).

Galileo already had a powerful patron in Cosimo II de’ Medici, Grand Duke of Tuscany and was also supported by the Roman aristocrat and patron of science, Prince Federico Cesi. But to secure even some degree of patronage from Pope Urban would have been a political and personal coup. It would also have potentially opened the door to bringing Copernicanism back onto the agenda. On October 9 1623, he wrote to Prince Cesi of his desire for an audience with the new Pope, saying:

I have in my head plans of no small importance for the learned world, and perhaps can never hope for so wonderful a combination of circumstances to ensure their success, at least so far as I am able to conduce to it. (von Gebler. p. 114)

This is very likely a veiled reference to a project that would, eventually, become the publication of the Dialogue Concerning the Two Chief World Systems (1633) and its fateful aftermath. Cesi encouraged Galileo to visit Rome and assured him “you will be very welcome to his Holiness”, as did others, including the Pope’s nephew, Cardinal Francesco Barberini, who wrote of a recent conversation with his uncle:

I swear to you that nothing pleased his Holiness so much as the mention of your name. After I had been speaking of you for some time, I told him that you, esteemed sir, had an ardent desire to come and kiss his toe, if his Holiness would permit it, to which the Pope replied that it would give him great pleasure. (von Gebler, p. 115)

Encouraged, Galileo travelled to Rome in April 1624 and with the help of his highly ranked supporters secured no less than six private audiences with Pope Urban over the space of six weeks. To have one audience with the Pope was a great honour. To have a private audience was more esteemed still. But to have six lengthy private conversations with the Pontiff was a sign of remarkable favour in a period in which such things were noticed and counted for a great deal. Galileo had effectively gained a very powerful patron.

Exactly what Pope Urban and Galileo discussed in these six interviews is not clear. It is often assumed they discussed the issue of Copernicanism and it is even sometimes claimed Galileo proposed the writing of his Dialogue to the Pope or that the Pope commissioned the work from him. But none of these things is clear from the evidence. In letters to Cesi written during his visit, Galileo refers to wanting to progress “some of the issues we [he and Cesi] discussed together” and, in a letter dated May 15, speaks of a meeting he had with Cardinal Eutel von Zollern;

I spoke at length with Cardinal Zollern on two occasions. Without being an expert in our field, he grasps the point at stake and knows what is to be done in this case. He told me that he wants to raise the matter with His Holiness before his departure in some eight or ten days from now. I shall gladly hear what he finds out, but there are so many issues that are considered infinitely more important than those I mentioned, and these absorb all the time available so that our questions are neglected. (Shea and Artigas, Galileo in Rome, p. 111)

Exactly what “the issues” and “the matter” referred to here is not made explicit, but it seems to have been the ban on Copernicanism. It is clear that even by this stage Galileo had not raised the issue with the Pope and hoped that Zollern would. Johann Faber, another friend of Galileo’s and Cesi’s, wrote to Cesi on May 23 that “I hope that Cardinal Zollern will be able to get something from the Pope concerning the Copernican system” (Shea and Artigas, p. 111), which confirms this was “the matter” in question and also that the issue had still not been discussed with Pope Urban. So it is hard to conclude Galileo had already done so in his audiences in April.

Cardinal Zollern did, however, finally broach the subject in an audience on June 7. Galileo reported to Cesi in a letter written the next day that Zollern had argued that “the heretics (i.e. Protestants) are all of [the Copernican] opinion and hold it as most certain” and so the Catholic Church “must go very circumspectly in coming to any determination”. In Galileo’s third hand report:

His Holiness responded that the Holy Church had not condemned it and nor was she about to condemn it now as heretical, but only as temerarious, though it was not to be feared that there would ever be anyone to demonstrate it as necessarily true. (A. Favaro, Edizione Nazionale delle Opere di Galileo, XIII 182, quoted in Annibale Fantoli, Galileo: For Copernicanism and for the Church, trans. G.V. Coyne, Vatican Observatory Publications, 1994, p. 302)

Of note here is Urban’s reported claim the Church had not and would not condemn Copernicanism as heretical. The 1616 injunctions had declared at least the proposition that the Sun was central to be “formally heretical”, though perhaps the Pope meant that he would not elevate this ruling to the level of dogma. He seems to have, by this report, regarded heliocentrism as merely “temerarious”, that is rash or reckless. The statement that he believed no one would ever be able to demonstrate the thesis indicates he held an Instrumentalist view; that the competing systems could never be proven and could therefore only ever be calculating devices. This was also reported by theologian Agostino Oregio, who recalled a conversation along similar lines with the then Cardinal Barberini before he became Pope:

[Barberini] asked …. whether God could not have the power and wisdom to dispose and move in another way the orbs and the stars and all that is seen in the sky …. Because if God knew how and had the power to dispose all of this in another way than that which has been thought: in such wise as to save all that has been said: we cannot limit the divine power and wisdom to this way. (quoted in Fantoli, p. 300)

So the Pope’s scientific positions on the matter was that no system could ever been proven and his theological one was that trying to do so was placing a limit on his divine omnipotence. But Galileo appears to have taken considerable encouragement from Cardinal Zollern’s report that Urban did not regard Copernicanism as heretical. This and other information and indications he had received in Rome, as well as the personal favour shown to him by the Pope, appears to have made him think the time was right to present his arguments in a new book, the one that was to become his Dialogue.

The writing of the book proceeded slowly over the next five years, interrupted by bouts of ill-health, the requirements of Galileo’s position at the court of the Grand Duke of Tuscany and side projects and disputes. He came back to it periodically, sometimes after putting it aside for long stretches of time. In a letter to his friend Elia Diodati of October 29 1629 he reported:

A month ago I took up again my Dialogue about the tides, put aside for three years on end … so that if I keep on this winter I hope to complete the work and publish immediately. (Quoted in Shea and Artigas, Galileo in Rome, p. 127)

At this stage he was still referring to the work as his “Dialogue about the tides”, because he intended his (erroneous) idea that the tides were caused by the rotation of the Earth to be its central argument: an early sign that he knowingly intended the book to favour the Copernican model over the Ptolemaic alternative. In this vein, he says in the same letter he is confident his book will provide “a detailed confirmation of the Copernican system with a demonstration of the futility of everything that was objected by Tycho and others”. So, at least in private correspondence with a friend, he is making no bones about his genuine intentions for the book. The reference to Tycho Brahe here is also notable, given the book was a debate about “the two chief world systems” (Copernican and Ptolemaic), but actually ignores the third prominent system – the Tychonian – despite it being widely accepted by most astronomers at the time. It seems he thought his arguments against Ptolemy would sufficiently account for Tycho as well, though many others would have disagreed. So Galileo “the Wrangler” was already skewing the argument in his desired direction.

His hopes to complete the book and “publish immediately” proved overly optimistic, however. The winter of 1629 had been as productive as Galileo hoped and on December 24 reported to Prince Cesi that his book was complete, apart from an introduction. But the road to actual publication proved difficult, dragging out for over a year and dogged by delays, setbacks, and complex negotiations over ecclesiastical permissions.

Galileo’s plan was to publish the work in Rome, under the imprint of Prince Cesi’s scientific society, the Accademia dei Lincei, and with a Papal imprimatur organised by the Master of the Sacred Palace, Niccolò Riccardi. Riccardi, who bore the colourful nickname “Father Monster” on account of his bulk, was very favourably disposed to Galileo and his office made him principal chaplain to the Papal court, the Pope’s main theological advisor and the chief censor of all books published in Rome. Thanks to some lobbying and flattery by Galileo’s enthusiastic fan, Benedetto Castelli (now a university lecturer in Rome), all signs were that Riccardi would smooth the way to publication. So on May 3 1630 Galileo arrived in Rome to finalise arrangements for publication. This involved more networking and lobbying, including another audience with Pope Urban on May 18. Riccardi received the manuscript of the Dialogue from Galileo and delegated review of it to a fellow Dominican, Father Raffaello Visconti, who was more literate in astronomical matters. On June 16 Visconti had an optimistic-seeming progress report for Galileo:

The Master [Riccardi] …. says he is pleased with the book and will talk about the frontispiece with the Pope tomorrow. As far as the rest is concerned, once a few small things, such as those we adjusted together, have been fixed, he will return the book. (Quoted in Shea and Artigas, Galileo in Rome, p. 143)

It seems Riccardi recognised the book was, in effect, a plea for Copernicanism. So Visconti had sat down with Galileo in Rome to moderate the argument and Riccardi, eager to please Galileo’s patron, the Tuscan Grand Duke, gave the impression all was almost ready to proceed to publication. Yet he did not yet give final permission or a formal imprimatur. Then Galileo suffered a major setback to his plans.

On August 1 1630 Prince Federico Cesi died suddenly, with no will, and so leaving both his Accademia Dei Lincei and Galileo’s plans for publication under its auspices in disarray. This led Galileo to seek to have his Dialogue published in Florence rather than Rome, which meant he had to get permission to publish from local authorities there, as well as agreement to this from Father Riccardi. He received local permissions by September 11, but “Father Monster” proved more of an obstacle. He insisted on seeing the full, final manuscript of the book, but this plan was obstructed by an outbreak of plague in central Italy, making easy travel, communication and delivery between Florence and Rome all but impossible.

Almost a full further year of back-and-forth negotiations about review, revision and permissions ensued, with Riccardi eventually allowing publication if he could at least review the introduction and conclusion and if the rest of the work was reviewed by a consultant to the Florentine Inquisition, Father Hyacinthe Stephani. On May 24 1631 Riccardi wrote to the Inquisitor-General of Florence, Clemente Egidi, effectively handing over responsibility for publication to him, but specifying what the Master of the Sacred Palace (and, therefore, Pope Urban) expected:

Your Very Reverend Paternity can avail yourself of your authority and dispatch or not dispatch the book without depending in any way on my review. However, I want to remind you that Our Master [the Pope] thinks that the title and subject should not focus on the ebb and flow [i.e. Galileo’s Argument from the Tides] but absolutely on the mathematical examination of the Copernican position on the Earth’s motion, with the aim of proving that, if we remove divine revelation and sacred doctrine, the appearances could be saved with this supposition; one would thus be answering all the contrary indications which may be put forth by experience and by Peripatetic philosophy, so that one would never be admitting the absolute truth of this opinion, but only its hypothetical truth without the benefit of Scripture. It must also be shown that this work is written only to show that we do know all the arguments that can be advanced for this side, and that it was not for lack of knowledge that the decree [of 1616] was issued in Rome. (Finocchiaro, Documentary History, p. 212)

So Riccardi was explicit that the title was not to reference the Argument from the Tides and this was not to be a focus of the book. Further, the book had to keep to the hypothetical and instrumentalist approach and show the 1616 decree was fully conversant with the relevant science. So the Dialogue was not to present or even imply the Copernican model was true. So, eventually, and after still further wrangling, the Dialogue came to be published on February 21, 1632. The reaction to it showed it was very clear that – thanks to this complicated, extended and irregular process of review, partial permissions, revisions, and political mediations – the end result was not what Father Riccardi and Pope Urban VIII had wanted at all.

(ii) The Reaction

A substantial initial run of one thousand copies of the Dialogue was printed, with a number officially presented to dignitaries and leading scholars, as was normal in this period. So as Galileo’s patron and final financial supporter of the publication, the Grand Duke of Tuscany Ferdinando II de’ Medici, received his copy in a ceremony on February 22, 1632, along with one for his French guest, Henri II de Lorraine, the Duc de Guise. The book’s dedication was full of the expected praise of the Grand Duke, followed by a preface in italics addressed “To the Discerning Reader”. It begins with a reference to the 1616 decree, called here “a salutary edict …. aimed at the dangerous tendencies of our present age” and the reaction to it by some, who “rashly asserted …. [that] consultants ought not to have clipped the wings of speculative minds by means of rash prohibitions”. This note goes on to declare “I [Galileo] propose in this work to show foreign nations that as much is understood about his topic in Italy, and particularly in Rome, as transalpine diligence can imagine” and that he will “make known that the Roman censors were perfectly well informed.” (Quoted in Shea and Artigas, Galileo in Rome, p. 160)

Given these sentiments reflect the position and the concerns of Pope Urban VIII, most of this section is likely the work of Riccardi, though its slightly coy reference to Galileo having “some previous notice [of the decree] …. given to me” – an oblique reference to the personal injunction to Galileo given by Bellarmine – was probably added by Galileo to whatever Father Monster had written for him. The next paragraph, on the other hand, is very unlikely to have been written or seen by Riccardi before publication:

To this end I have taken the Copernican side in the discourse and, proceeding as with a pure mathematical hypothesis, I have tried to show, by every means, that it is more satisfactory than supposing the Earth motionless – not, indeed, absolutely, but when compared to the arguments of some professed Peripatetics, who do not even deserve that name. (Quoted in Shea and Artigas, Galileo in Rome, pp. 160-61)

Here Galileo comes as close as he can to openly stating he is presenting an argument for Copernicanism, hedged only by a few slightly modifying words and phrases. This is, at best, sailing very close to the rhetorical wind for a book that, on its own title page, declares itself to be “as much for one side as another”.

Anyone reading the book could, then as now, see it is absolutely not an even-handed and objective analysis of the competing views. In the Dialogue, Galileo’s stand-in, Salvati, has all the best arguments, all the best lines and is clearly the hero of the book. His opponent, Simplicio, is deliberately unimpressive in his style and his arguments, and by the end even the supposedly neutral host Sagredo – a stand-in for the intelligent layman reader – is convinced by Salvati and joins him in trying to convince Simplicio. The book ends, despite Riccardi’s instructions to the contrary, with Salvati triumphantly presenting Galileo’s Argument from the Tides in some detail. It then closes with a slightly cursory presentation of the Instrumentalist views of Riccardi and Pope Urban by Simplicio, noted to be “a most solid doctrine that I once heard from a most eminent and learned person, and before which one must fall silent”. Salvati responds, agreeing that this is “an admirable and angelic doctrine” and adding “another one, also Divine, which, while it grants to us the right to argue about the constitution of the universe (perhaps in order that the working of the human mind shall not be curtailed or made lazy), adds that we cannot discover the work of His hands.” (Finocchiaro, Documentary History, pp. 217-18)

So, as per his declared intention while writing it, Galileo is obviously doing all he can to emphasise the Copernican case while staying just within the letter of the law regarding objectivity and the parameters imposed on him by Urban and Riccardi. Once again an outbreak of plague and restrictions on travel and commerce between Florence and Rome delayed the delivery of copies of the book to various luminaries in Rome, so the reaction to it there was delayed by several months. But it came in July. In a seemingly hurried letter of July 25, 1632, Riccardi wrote to the Florentine Inquisitor Clemente Egidi:

Galileo’s book has arrived and there are many things that are not acceptable and that the authorities want to see revised. The Sovereign Pontiff has ordered (but only mention my name) that the book is to be withheld. It should not be sent here [Rome] until you receive what is to be corrected, nor should it be sent elsewhere. (Quoted in Shea and Artigas, Galileo in Rome, p. 164)

Even more significant is a hasty postscript to this letter:

Let me know as soon as possible whether the device with the three fish is the printer’s or Galileo’s and write to tell me what it means.

This refers to the symbol that appears on the book’s title page: an image of three fish each connected to each other by their mouths. That this was something Riccardi needed information on so urgently is a clue to what was happening in Rome.

Pope Urban had elevated several of his relatives to senior positions in the Church, with his brother, Antonio Marcello Barberini, and his nephews, Francesco Barberini and Antonio Barberini the Younger all made Cardinals and given high offices in the Vatican. As a result, Pope Urban was highly sensitive to accusations of nepotism. A letter by Lorenzo Magalotti to Benedetto Castelli’s associate, Mario Guiducci (7 August 1632), detailing the reaction to the Dialogue in Rome mentions the rumour that this fish symbol on the title page was a satire on Urban’s nepotism, with the motto “Grandior ut proles” (I have grown as my family) alleged to be making the point even more sharply. Riccardi was apparently relieved to learn the symbol and motto were actually a logo of the printer, Landini, and appeared on most books he produced. But the rumour and investigation shows that the Pope was on edge about his reputation and how the book may damage it.

To understand why, we have to do something Galileo apparently did not do: examine the volatile political and diplomatic context in which the book arrived. Apart from his status as the head of the Catholic hierarchy, Pope Urban was also the ruler of a relatively small central Italian state; one which, due its size and the precarious nature of Papal finances, was dependent on alliances and diplomacy to avoid any military threats. For over a century the Popes had done this by cultivating the support and protection of the two superpowers of Early Modern Europe: the Kingdom of France and the Kingdom of Spain, often playing one off against the other. And in the period immediately before the pontificate of Urban VIII the Popes had depended heavily on Spain, whose Habsburg rulers were also Holy Roman Emperors. Spain made for a powerful ally, though the price was a high degree of Spanish influence on Papal policy and of dominance by Spanish Cardinals in the Vatican.

This shifted with developments in the course of the ongoing Thirty Years War. What began in 1618 as a largely local conflict between Catholic and Protestant principalities in the Holy Roman Empire and then spiralled outward into a war across much of western and central Europe, dragging in the richest and most highly militarised major powers of the day, such as Sweden, Spain and France. The success of the Spanish Habsburgs in the first phase of the war led to a fear by France that they would be encircled by their traditional continental enemies. The French increasingly supported Spain’s opponents, even if they were Protestants, and the war evolved into a struggle for European dominance between France and Spain.

Spain controlled most of southern Italy as well as the Duchy of Milan, and had alliances and strong influences over Genoa, the Duchy of Savoy and the Duchy of Mantua. This meant King Philip IV had territory and powerful support both to the north and the south of the Papal States when Urban came to the pontificate. With its control of the southern Netherlands, Luxembourg, and Franche-Comté, and allied kinsmen ruling in Lorraine and parts of the Holy Roman Empire, Spain was a clear threat to France. So French policy, determined by the able diplomatic strategist and Louis XIII’s chief minister Cardinal Richelieu, sought to increase French power in Italy and French influence in the Vatican.

The election of Urban VIII was therefore a coup for Richelieu and the French. As David Marshall Miller explains in a key paper on the geopolitical and diplomatic context of the Galileo Affair:

Cardinal Barberini had a fondness for France. He had earned the cardinal’s purple by serving as Papal Nuncio in Paris, and had baptized [King] Louis. He was therefore favoured by the cardinals aligned with France, who overcame the opposition of the powerful Habsburg ‘faction’ and the Spanish king. Urban’s election effectively ended Spain’s domination of Roman affairs and threatened Spain’s hegemony on the Italian peninsula. (D.M. Miller, “The Thirty Years War and the Galileo Affair”, History of Science, 46 (1), pp.49-74. p. 58)

Things came to a head on Christmas Day 1627, when the Duke of Mantua died without a son. The rightful heir was a French noble, but the Spanish did not want to see one of their Italian allies switch to French domination and threaten the vital flow of men and materiel between Spain, Germany, and the Low Countries along the so-called “Spanish Road”. So by 1629 the French and the Spanish were at war in Mantua and Pope Urban supported the French. The Spanish were not pleased. The Pope helped negotiate a peace in Mantua between the two sides in 1631, but French influence in Italy had strengthened as a result of the clash. The intervention of the powerful and militarily able Lutheran King of Sweden, Gustavus Adolphus, into the Thirty Years War in 1630 led to more battlefield reverses for the Habsburgs and Spain. By 1632 Adolphus, with French support, invaded Bavaria and by May a Swedish invasion of Italy seemed imminent. Recriminations against those seen as responsible for these disasters were flying at the Papal court, with Spanish Cardinals pointing the finger at Pope Urban.

On 8 March 1632 the Spanish ambassador to Rome, Cardinal Gasparo Borgia, stood to read a statement that concluded ” … any injury suffered by the Catholic religion must be ascribed not to himself, the most pious and obedient King [Philip IV of Spain], but to Your Holiness.” At this point the angry Pope himself interrupted Borgia, the meeting descended into a shouting match and the Swiss Guard had to be deployed to restore order. Undeterred, Cardinal Borgia had his condemnation published and rumours swirled that not only was the Pope in league with the Protestants, but he was secretly a Protestant himself. Caught in this diplomatic maelstrom, Pope Urban was being accused of heresy and there was even talk of his outright deposition as Pope.

And it was in this wild military, diplomatic and geopolitical context that Galileo chose to publish his Dialogue; a book clearly perceived to be heretical and yet apparently published with the full approval of Pope Urban himself. Pope Urban was, understandably, absolutely furious with Galileo and needed to make an example of him as clearly and powerfully as possible.

As an aside, it should be noted that this political embarrassment and the Pope’s reaction to it is usually ignored in popular accounts of the Galileo Affair. Instead, it is regularly claimed that the “real” reason for Urban’s anger was that Galileo’s book lampooned him by putting his arguments in the mouth of the dialogue’s Simplicio – a name, it is argued, which could be interpreted as “the Simpleton” or “the Fool” (it is actually the Italian form of Simplicius, the name of an ancient commentator on Aristotle, and so indicates a conservative Aristotelian). So this, it is claimed, was the actual trigger of the trial and all that followed. As popular as this neat story may be, it has serious flaws and is most likely not correct. As mentioned above, we have evidence of what angered Pope Urban and of what other possible slights against the Pope were explored. So the “three dolphins” logo was investigated as a possible satirical reference to nepotism, though ultimately dismissed. But there is no mention of this “simpleton” idea in any of this pre-Trial source material. It is first mentioned in 1635, so two years after Galileo’s trial, in a letter to Galileo by Castelli, who refers to it as a rumour going around. Finocchiaro does not dismiss the idea completely, but agrees with earlier scholars who think it was a bit of later gossip and not an actual motivation for the trial:

Although this claim is plausible, the fact remains, as Sante Pieralisi argued in 1875, that this accusation is not mentioned in any documents prior to December 1635; it is not mentioned even in Magalotti’s letter to Guiducci of 7 August 1632, which mentions the rumor that the three dolphins of the publisher’s trademark were a caricature of Urban’s nepotism. Thus, it seems more accurate to regard the Simplicio-as-Urban allegation as a new slander against Galileo. (Finocchiaro, Retrying Galileo, p. 62)

What we do have, however, is evidence that the Dialogue had damaged Urban politically. When word reached Florence that the book had not been well-received in Rome, the Grand Duke tried to intervene on behalf of his client. When it first appeared that Galileo would be sanctioned, the Tuscan ambassador in Rome, Francesco Niccolini, tried to defend Galileo but received an angry response. Writing to the Tuscan Secretary of State, Bali Cioli, on 5 September 1632, he reported the meeting with the Pope had “transpired in a very emotional atmosphere”:

While we were discussing those delicate subjects of the Holy Office, His Holiness exploded into great anger, and suddenly he told me that even our Galilei had dared entering where he should not have, into the most serious and dangerous subjects which could be stirred up at this time. (Finocchiaro, Documentary History, p. 229)

In a later letter to Cioli (11 September) he reported:

In fact, the Pope believes that the Faith is facing many dangers and that we are not dealing with mathematical subjects here but with Holy Scripture, religion, and Faith. (Finocchiaro, Documentary History, p. 229)

He could have added “politics” to this list. On 17 September 1631, the Protestants had crushed the Catholic army at Breitenfeld near Leipzig, destroying an estimated two-thirds of the defeated army. In the spring of 1632 the Swedish Army had invaded Catholic Bavaria, had secured passage through Switzerland and appeared on the brink of an invasion of Italy. As Miller summarises the situation:

Urban had weightier matters than Copernicanism in mind. At that time, the greatest danger the Church faced was the aftermath of Breitenfeld and the Protestant army just across the Alps, a situation for which Urban was blamed. The Pope needed to make an example of someone, and Galileo was his man. (Miller, p. 62)

The Grand Duke was told in no uncertain terms that the Pope was prepared to break relations with Tuscany if he obstructed any action against Galileo and on 30 December 1632, after attempts at delay by Galileo, the Inquisition issued a final order for him to come to Rome. Threatened with arrest if he delayed further, Galileo complied.

(iii) The Trial

The mythological version of the Galileo story has him being arrested, taken to Rome, held in a dungeon, and then either interrogated in a cell with torture devices around him or standing in chains before a tribunal made up of the Pope and various cardinals. None of this is accurate. Galileo arrived in Rome on 13 February, after a journey delayed by another outbreak of plague. The Tuscan ambassador Francesco Niccolini requested that he be housed in the Tuscan embassy, the Palazzo Firenze, where he waited for several weeks, in comfort, though with restrictions on his movements, while both the ambassador and the Grand Duke made unsuccessful entreaties on his behalf. Pope Urban was not moved, however, and on 12 April he faced a tribunal of the Holy Office in the Inquisition’s headquarters, the Palazzo del Sant’Uffizio.

Far from being held in some kind of dank cell, the trial took place in a meeting room in this palazzo, which is also where Galileo was given comfortable apartments for its duration, complete with meals cooked by the Grand Duke’s Roman chef and brought from the Villa Medici. And instead of the grand affair in front of multiple high-ranking prelates imagined by later artists, it was presided over by just two officials: the Inquisition’s Commissary-General, Father Vincenzo Maculano, and probably his assistant prosecutor, Father Carlo Sinceri, attended by a few notaries (see Henry Ansgar Kelly, “Galileo’s Non-Trial (1616), Pre-Trial (1632–1633), and Trial (May 10, 1633): A Review of Procedure, Featuring Routine Violations of the Forum of Conscience”, Church History, 2016, 85(4), pp. 724-76 for a detailed analysis of the mechanics of the trial)

The Galileo mythology also imagines a titanic battle of wits, with Galileo grandly and eloquently defending his scientific reasoning and the inquisitors quailing before the power of his logic and reason. Again, it was nothing like this. This is possibly what Galileo had imagined it would be, but Pope Urban had other ideas. Back on 13 March, Ambassador Niccolini had an audience with the Pope where he assured him that Galileo “if he is heard …. will easily give every satisfaction”. His letter to the Tuscan Secretary of State goes on:

He replied that Mr. Galilei will be examined in due course, but there is an argument which no one has ever been able to answer: that is, God is omnipotent and can do anything; but if He is omnipotent, why do we want to bind him? I said that I was not competent to discuss these subjects, but I had heard Mr. Galilei himself say that first he did not hold the opinion of the Earth’s motion as true and then that since God could make the world in innumerable ways, one could not deny that He might have made it this way. However, he got upset and told me that one must not impose necessity on the blessed God; seeing that he was losing his temper, …. I said that, in short, he was here to obey and to retract everything for which he could be blamed in regard to religion [then] …. I changed the subject. (Finocchiaro, Documentary History, p. 247)

Clearly Pope Urban was in no mood for debate and had fixed firmly on his theological position about any preferred position on the matter limiting God’s omnipotence. For him, the trial was simply to get Galileo to admit his error and publicly abjure. As the date of the trial drew near, Niccolini did his best to make this clear to Galileo. In a later letter to Cioli he says:

Nevertheless, Mr. Galilei tries to defend his opinions very strongly; but I exhorted him, in the interest of a quick resolution, not to bother maintaining them and to submit to what he sees they want him to hold or believe about that detail of the Earth’s motion. He was extremely distressed by this, and, as far as I am concerned, since yesterday he looks so depressed that I fear greatly for his life. (Finocchiaro, Documentary History, p. 247)

Galileo “the Wrangler” was finally beginning to realise this was a political situation, and one he could not argue his way out of.

Galileo was taken by carriage from the Tuscan Embassy to the Palazzo del Sant’Uffizio, to face a pre-trial interrogation by the Inquisition’s Commissary-General, Father Vincenzo Maculano on April 12, 1633. After some preliminary questions about himself and his book, Maculano turned to his earlier visit to Rome in 1616, asking the purpose of that visit. Galileo replied “having heard objections to Nicolaus Copernicus’ [thesis] ….I came to hear what was proper to hold in regard to this topic” (Finocchiaro, Documentary History, p. 257). In response to further questioning as to what he was told on this subject and by whom, Galileo referred to his meeting with Cardinal Bellarmine on February 26, 1616, whereupon Maculano asked him “precisely” what “was decided and then made known to him” on that occasion. Galileo responded by playing what he thought might be his trump card:

Lord Cardinal Bellarmine told me that since Copernicus’s opinion, taken absolutely, was contrary to Holy Scripture, it could be neither held nor defended, but it could be taken and used suppositionally. In conformity with this I keep a certificate by Lord Cardinal Bellarmine himself, dated 26 May 1616, in which he says that Copernicus’s opinion cannot be held or defended, being against Holy Scripture. I present a copy of this certificate, and here it is. (Finocchiaro, Documentary History, p. 259)

Galileo then produced for the court the certificate he had requested of Bellarmine to counter the rumours put about by “the Pigeon League” he had been accused of heresy, found guilty and abjured. He had taken both the original of this document, which he noted was “written all in the hand of the above-mentioned Lord Cardinal Bellarmine”, and a copy which he now handed to the tribunal because he thought this would be his “Get Out of Jail Free Card”. Unfortunately for him, Bellarmine’s note did not actually detail exactly what he had promised in 1616, and merely stated more generally that he had been informed “the doctrine attributed to Copernicus …. could not be defended or held”.

The tribunal, on the other hand, definitely did know what he had sworn before Bellarmine, given it had found in its files the case note that recorded his meeting with Bellarmine and detailed exactly what was sworn. So Maculano then asked to recall any injunction given to him that day, and Galileo replied that “as I remember it” Bellarmine had said “that Copernicus’s opinion could not be held or defended, being contrary to Holy Scripture” – so, essentially what his certificate said.

Maculano then asked “if one were to read to him what he was then told and ordered with injunction, he would remember that.” At this point Galileo seems to have realised they may know more than he thought and that the ground was shifting beneath him. He replied “I do not recall that I was told anything else, nor can I know whether I shall remember what was then told me, even if it is read to me.” The case note of the private injunction of February 26, 1616, was then read to him, including its key words, which were missing from both Bellarmine’s later certificate and, it appears, from Galileo’s memory:

Most Illustrious Lord Cardinal [Bellarmine] warned Galileo that the abovementioned opinion [Copernicanism] was erroneous and that he should abandon it; and thereafter, indeed immediately, before me and witnesses, …. ordered and enjoined the said Galileo …. to abandon completely the abovementioned opinion …. and henceforth not to hold, teach, or defend it in any way whatever, either orally or in writing. (Finocchiaro, Documentary History, p. 147, my emphasis)

This last element was the critical point on which the Inquisition’s case turned, and Galileo seems to have realised this immediately. His response was essentially that his memory was probably faulty on this point, perhaps because it relied on the vaguer terms in Bellarmine’s certificate:

I do not recall that this injunction was given me any other way than orally by Lord Cardinal Bellarmine. I do remember that the injunction was that I could not hold or defend, and maybe even that I could not teach. I do not recall, further, that there was the phrase in any way whatever, but maybe there was; in fact, I did not think about it or keep it in mind, having received a few months thereafter Lord Cardinal Bellarmine’s certificate dated 26 May which I have presented and in which is explained the order given to me not to hold or defend the said opinion. Regarding the other two phrases in the said injunction now mentioned, namely not to teach and in any way whatever, I did not retain them in my memory, I think because they are not contained in the said certificate, which I relied upon and kept as a reminder. (Finocchiaro, Documentary History, p. 260)

So Galileo appealed immediately to his faulty memory, but he knew he was now in genuine trouble. The certificate he thought would have saved him had now proven to be trumped by the Inquisition’s better documentary evidence.

The centrality of this document to the trial means that some have tried to argue it was an outright forgery; faked by the Inquisition in 1633 to determine the outcome of the trial. This was argued in detail in a pamphlet by Emil Wohlwill (Der Inquisitionsprocess des Galileo Galilei: Eine Prüfung seiner rechtlichen Grundlage nach den Acten der Römischen Inquisition, Hamburg, 1870) and was supported by some nineteenth century scholars. As a result, it is still presented as though it is a credible idea. In January 2021 the young atheist polemicist Alex O’Connor, who posts videos as “the Cosmic Skeptic”, presented a dubious and error-laden account of the Galileo Affair with the remarkably bold title “The Trial of Galileo: What Really Happened?” (19 December, 2019). Among many blunders (see “Cosmic Skeptic Bungles Galileo” for a full critique), he effectively tells his audience of over two million subscribers that this key piece of evidence was a forgery.

Unfortunately for the endlessly confident O’Connor, this is nonsense and has been rejected by all modern historians. The document in question survives and so by the end of the nineteenth century it was possible for scholars to determine that it was contiguous with the 1616 documents before and after it in the relevant volume, so it was not some later insertion. Further, between 1926 and 1929 Rudolf Lämmel did physical tests on the manuscripts pertaining to the Galileo trial, including the 1616 injunction note. As Finocchiaro notes:

The tests involved examining the manuscripts with X rays and ultraviolet light. The result was that there were no signs that previous writing had been erased and new words written over in any of the problematic documents, such as the special injunction transcript of 26 February 1616 and the rigorous-examination deposition of 21 June 1633. This further confirmed that the file did not contain falsified documents of the kind conjectured by Wohlwill’s and Scartazzini’s forgery theses, as Gebler had already convincingly shown by more traditional arguments. (Finocchiaro, Retrying Galileo, p. 262)

So O’Connor is completely wrong and demonstrates he has no grasp of the relevant scholarship. Some debate remains about whether the note genuinely reflects what was said to Galileo and what its legal status in the 1633 trial actually was (see Finocchiaro, “Authenticity vs. Accuracy vs. Legitimacy: Pagano on the Vatican Documents” in Science, Method, and Argument in Galileo, vol. 40, Cham: Springer, 2021, pp. 337–353 on these issues), but there is no doubt it was genuine and formed the basis for a very strong case against Galileo.

This was driven home by Maculano, who proceeded to ask Galileo if he had sought permission, after receiving this highly explicit and specific injunction, to write and publish his Dialogue. Galileo responded by making the rather extraordinary claim that he did not feel the need to do so because “I do not think that by writing this book I was contradicting at all the injunction given me not to hold, defend, or teach the said opinion, but rather that I was refuting it”. Questioned further, he gave a summary of his dealings with “Father Monster”, Niccolò Riccardi, and the Florentine Inquisition (see above). Maculano then asked if, in the course of these proceedings, he ever mentioned to Riccardi the 1616 injunction. Galileo replied:

When I asked him for permission to print the book, I did not say anything to the Father Master of the Sacred Palace about the above-mentioned injunction because I did not judge it necessary to tell it to him, having no scruples since with the said book. I had neither held nor defended the opinion of the Earth’s motion and Sun’s stability; on the contrary, in the said book I show the contrary of Copernicus’s opinion and show that Copernicus’s reasons are invalid and inconclusive. (Finocchiaro, Documentary History, pp. 261-2)

So, once again, Galileo chose to defend himself by claiming his book actually argues against Copernicanism. A rather odd strategy, though perhaps the best he could think of having just been rattled by the document produced against him. It was to prove a bad choice.

As already noted, Galileo had stated explicitly in his letter to his friend Elia Diodati (October 29, 1629) that he intended his book provide “a detailed confirmation of the Copernican system with a demonstration of the futility of everything that was objected by Tycho and others”. And his introduction to the Dialogue had been almost as explicit, stating “I have taken the Copernican side in the discourse and, proceeding as with a pure mathematical hypothesis, I have tried to show, by every means, that it is more satisfactory than supposing the Earth motionless – not, indeed, absolutely, but when compared to the arguments of some professed Peripatetics”. This last statement is hedged somewhat, but his intention is obvious to anyone who reads the book: he clearly favours the Copernican Model and wants his audience to do so as well. So to now claim his book argues against Copernicanism was a tenuous line of defence.

The Inquisition duly put the question of what the book did or did not argue to three Consultants, asking them to read the Dialogue and report on whether it defended the Copernican position. These assessors were the theologians Agostino Orregi, Melchior Inchofer and Zaccaria Pasqualigo. All three came to the same conclusion: that it did. Orregi’s report was brief, but it refers to an earlier report “which, by order of His Holiness, the very reverend Father Niccolò Riccardi, Master of the Sacred Apostolic Palace, and [myself] presented to the Most Eminent and Most Reverend Cardinals Inquisitors-General”. That seems to be an account of the wrangling and negotiation of Galileo’s permission to publish the Dialogue, presented to the Inquisition back in September 1632 and which also contained an assessment of the book’s stance on heliocentrism.

Pasqualigo and, particularly, Inchofer went into much more detail in their reports, also delivered on 17 April 1633. Each cited specific passages and arguments in the Dialogue that they felt made it clear that it was not an even-handed and objective analysis, but an overt argument for the Copernican position. So Galileo’s defence that he actually argued against heliocentrism was not going to cut much ice with the tribunal.

But this tactic by Galileo posed a problem for Father Maculano. The trial was supposed to be more or less a political show. Galileo had been convinced beforehand by the Florentine ambassador, Francesco Niccolini, that defending his scientific position was pointless and it was expected that he would simply fold, confess and receive a penance. This unexpected line of argument that he had argued against Copernicanism certainly did not stand up to scrutiny, but it could also extend the trial, which Pope Urban clearly wanted quickly concluded with the desired capitulation by Galileo. Maculano was from Florence himself and understood the Pope wanted a political outcome to placate the Spanish, but also that an extended trial could strain Papal relations with Galileo’s patron, the Grand Duke of Tuscany. So, what to do?

At a meeting of the Inquisition on 27 April, Father Maculano proposed a way to expedite the Pope’s desired outcome: “I proposed a plan, namely [that I] deal extrajudicially with Galileo, in order to make him understand his error and, once having recognized it, to bring him to confess it” (Finocchiaro, Documentary History, p. 276). The Inquisitors were initially sceptical but finally granted Maculano authority to try this approach. Writing to Cardinal Francesco Barberini the next day, Maculano reported success:

Yesterday afternoon I had a discussion with Galileo, and, after exchanging innumerable arguments and answers, by the grace of the Lord I accomplished my purpose: I made him grasp his error, so that he clearly recognized that he had erred and gone too far in his book; he expressed everything with heartfelt words, as if he were relieved by the knowledge of his error; and he was ready for a judicial confession. However, he asked me for a little time to think about the way to render his confession honest

Maculano had clearly discussed the desired outcome here with both Cardinal Barberini and his uncle, the Pope, because he adds that he is confident his result will achieve what they wanted:

The Tribunal will maintain its reputation; the culprit can be treated with benignity; and, whatever the final outcome, he will know the favor done to him, with all the consequent satisfaction one wants in this. I am thinking of examining him today to obtain the said confession; after obtaining it, as I hope, the only thing left for me will be to question him about his intention and allow him to present a defense. With this done, he could be granted imprisonment in his own house, as Your Eminence [Cardinal Barberini] mentioned. (Finocchiaro, Documentary History, p. 277)

So, the Pope would get his public confession by Galileo, the trial would conclude quickly and Galileo would know he had been treated with respect and a degree of leniency.

Three days later, on 30 April, Galileo duly re-entered Maculano’s office for a second deposition. He declared that he had just re-read his book and discovered, to his surprise, that it did indeed give the strong impression of “arguments for the false side”. He said that “not having seen it for so long, I found it almost a new book by another author”, and assured the Commissioner that he had no intention of “disobedience”, insisting that:

I resorted to that of the natural gratification everyone feels for his own subtleties and for showing himself to be cleverer than the average man, by finding ingenious and apparent considerations of probability even in favor of false propositions. …. My error then was, and I confess it, one of vain ambition, pure ignorance, and inadvertence. This is as much as I need to say on this occasion, and it occurred to me as I reread my book. (Finocchiaro, Documentary History, p. 278)

He then signed this statement and left. But, rather remarkably, he returned “after a little” and offered to add “one or two other Days” to an amended edition of the Dialogue to unequivocally refute Copernicanism. There is no record of any response to this offer and the Inquisition certainly did not allow it. As Shea and Artigas say “This was Galileo’s last card, and he played it in the hope of saving his book from outright condemnation” (Galileo in Rome, p. 190). This last gambit failed.

There followed a two week break in proceedings, which Galileo spent, once again, at the Tuscan embassy. On 10 May he returned to the Palazzo del Sant’Uffizio where he submitted a written statement he had clearly worked on in the intervening period. In it he tried to explain why he had not informed Niccolò Riccardi or the Florentine Inquisition about the 1616 injunction forbidding him to discuss heliocentrism. Once again, he referred to his certificate from Cardinal Bellarmine of 26 May 1616, explaining that this had been his aide de memoire regarding what he had been ordered in 1616 and so he had accepted its much broader terms (“[heliocentrism] could not be defended or held”) rather than the much more stringent restriction recorded in the Inquisition’s case note (“not to hold, teach, or defend [heliocentirsm] in any way whatever, either orally or in writing”).

I do not think I should be mistrusted about the fact that in the course of fourteen or sixteen years I lost any memory of them, especially since I had no need to give the matter any thought, having such a valid reminder in writing. Now, when those two phrases are removed and we retain only the other two mentioned in the attached certificate, there is no reason to doubt that the order contained in it is the same as the injunction issued by the decree of the Holy Congregation of the Index. From this I feel very reasonably excused for not notifying the Father Master of the Sacred Palace of the injunction given to me in private, the latter being the same as the one of the Congregation of the Index. (Finocchiaro, Documentary History, p. 280)

This defence essentially boils down to Galileo quickly forgetting the more stringent injunction, which doe not seem to have convinced the tribunal. The remainder of his statement emphasised his “declining old age”, ill health, the long journey he had made from Florence and “ten months of constant mental distress”, and so appealed for clemency.

Nearly a month and half would pass before the tribunal took up Galileo’s case again. Minutes of a meeting of the Inquisition on 16 June attended by Pope Urban indicate a direct order by the Pope to wrap the trial up with the desired abjuration and public condemnation. A final interrogation of Galileo regarding his intentions when writing the Dialogue was ordered, along with very explicit instructions regarding the outcomes if Galileo was to maintain his insistence that he did not intend to argue for Copernicianism in his book:

His Holiness decided that the same Galileo is to be interrogated even with the threat of torture; and that if he holds up, after a vehement abjuration at a plenary meeting of the Holy Office, he is to be condemned to prison at the pleasure of the Sacred Congregation, and he is to be enjoined that in the future he must no longer treat in any way (in writing or orally) of the Earth’s motion or Sun’s stability, nor of the opposite, on pain of relapse; and that the book written by him …. is to be prohibited. (Finocchiaro, Retrying Galileo, p. 247)

So on 21 June Galileo returned to the Holy Office for a fourth deposition, where he was questioned very specifically about his position, both current and in the past, on the Copernican model:

Q: Whether he holds or has held, and for how long, that the Sun is the center of the world and the Earth is not the center of the world but moves also with diurnal motion.

A: A long time ago, that is, before the decision of the Holy Congregation of the Index, and before I was issued that injunction, I was undecided and regarded the two opinions, those of Ptolemy and Copernicus, as disputable, because either the one or the other could be true in nature. But after the above-mentioned decision, assured by the prudence of the authorities, all my uncertainty stopped, and I held, as I still hold, as very true and undoubted Ptolemy’s opinion, namely the stability of the Earth and the motion of the Sun. (Finocchiaro, Documentary History, p. 286)

So here Galileo makes an unequivocal rejection of Copernicanism and states clearly that he holds the Ptolemaic model to be “very true and undoubted”. But Maculano’s instructions were to get him to admit he had intended to argue for Copernicanism when he wrote the Dialogue, and all parties involved had good reason to believe this claim that he had fully changed his view after 1616 was simply untrue. So Galileo was told “he is presumed to have held the said opinion after that time, from the manner …. in which the said opinion is discussed and defended in the book he published after that time”. But Galileo stuck to his position that he dropped any heliocentric view after 1616.

I did not do so because I held Copernicus’s opinion to be true. Instead, deeming only to be doing a beneficial service, I explained the physical and astronomical reasons that can be advanced for one side and for the other; I tried to show that none of these, neither those in favor of this opinion or that, had the strength of a conclusive proof …. I have not held the condemned opinion. (Finocchiaro, Documentary History, p. 287)

Maculano tried a third time, insisting that the Dialogue shows he held a Copernican position and urging Galileo “unless he decided to proffer the truth, one would have recourse to the remedies of the law and to appropriate steps against him”. Once more Galileo insisted that he did not hold the Copernican position. And here, in the tribunal’s response, we find the only reference to torture in the trial.

And he was told to tell the truth, otherwise one would have recourse to torture. (Finocchiaro, Documentary History, p. 287)

Contrary to the mythological version of the trial, where Galileo defiantly defends heliocentrism and only recants his position when threatened with torture, here we see Galileo explicitly rejected the Copernican position and states the Ptolemaic model as “very true and undoubted” no less than three times in succession, and before the one and only mention of torture in the proceedings. At this point Galileo insists on his previous statements, saying for the fourth time “I have not held this opinion after the determination was made, as I said”. There proceedings end for the day.

Since the issue of the threat of torture is central to the mythological version of the Galileo story, it is important to examine its role in the actual trial in more detail. In most popular versions of the Galileo story, he bravely defends the science behind heliocentrism and, understandably, only reluctantly recants under threat of torture. In a 2009 televised debate on the proposition “The Catholic Church is a Force for Good in the World”, the case against was argued successfully by two prominent atheists: the journalist Christopher Hitchens and actor and comedian, Stephen Fry. At one point, Fry spoke with great passion about “Galileo and the fact that he was tortured, for trying to explain the Copernican theory of the Universe” adding with strong emphasis “That’s history! History!” This is despite the fact that is was not a “fact” at all and that this “history” simply did not happen.

Only slightly less embarrassingly silly is another blunder by Alex O’Connor, aka “The Cosmic Skeptic”. On several occasions he has spoken emphatically about how “Galileo was shown the instruments of torture”, wielding this evocative image as evidence of the intolerance of religion in the face of science. Speaking with his usual great self-assurance, in a Durham Union debate on “God is Dead”, (2 April 2025) O’Connor declares:

I know that Galileo was shown the instruments of torture by the Inquisition for having the temerity to suggest that perhaps the Earth might [orbit] with the Sun rather than the other way around. (6.16 mins)

This seems to be a well-polished line for O’Connor, since he used identical words when he rolled it out in conversation with conservative American commentator, Ben Shapiro (Alex O’Connor vs Ben Shapiro: The Atheist Delusion, Free Will and the Future of Society, 2 Dec 2023, 38.53 mins). Perhaps someone educated O’Connor on this matter after his Durham Union debate, because in conversation with Oxford mathematician John Lennox (Why This Oxford Mathematician is Confident God Exists, 23 May 2025, 9.28 mins), he tones down his claim, this time saying “This idea he was tortured for his beliefs is a mistaken one. Though, allegedly, some people believe he was shown the instruments of torture, as if to say … keep quiet.” But there is no basis for any of this. To begin with, as we have seen, Galileo found himself on trial for doing far more than merely “suggesting” heliocentrism was true. Secondly, the only mention of torture in the trial, as noted above, was not made to make him “keep quiet”, but rather because what he was saying at that point was clearly a lie. Finally, the whole “he was shown the instruments of torture” idea has absolutely no basis in any of the documents around the trial.

Showing the accused the instruments of torture was the second step in the five step process used by Inquisitions when it came to torture. As both lawyers and theologians, inquisitors were sticklers for rules and process and Early Modern jurists like Giulio Claro detailed the well-established procedure:

“Know then that there are five degrees of torture: first, the threat of the rack; second, being taken into the torture chamber; third, being undressed and bound; fourth, being laid upon the rack; fifth, turning the rack.” (Claro, quoted in von Gebler, Ch. 10; see also Finocchiaro, Retrying Galileo, p. 11)

Each of these steps was documented in the trial proceedings and the process could be halted at each point. As Galileo’s trial transcript shows, in his case the process did not proceed further than the first step: a territio verbalis or threat of torture. If it had proceeded to the rather more serious second or any subsequent steps, it would have been noted. So where has O’Connor got this idea that he was “shown the instruments of torture”? While it was posited by Emil Wohlwill in 1877, it was not generally accepted by other Galileo scholars at the time or since. But it was widely popularised by the play Life of Galileo by the German playwright Bertolt Brecht. This play first premiered in its German version in Zurich in 1943 and then in English in Los Angeles in 1947, and it seems to be the source of many popular misconceptions about the Galileo Affair. In it (Scene Twelve), Pope Urban is depicted in conversation about the Galileo’s trial with an unnamed character called simply “The Cardinal Inquisitor”. This character assures the Pope that:

Practically speaking one wouldn’t have to push it very far with him. He is a man of the flesh. He would give in immediately.

Soon afterwards, the Pope instructs the Inquisitor:

At the very most he can be shown the instruments.

In the play’s final scene (Scene Fourteen) Galileo tells a friend:

I recanted because I was afraid of physical pain. …. They showed me the instruments.

As is often the case, the widespread myth that Galileo was “shown the instruments” is one that can be traced to a popular work of fiction, not something found in any documents from the trial. Unfortunately the influence of Brecht’s dramatic scenes mean many popular writers continue to state this myth as though it is documented historical fact.

So the remaining historical question is whether the threat of torture was serious and was Galileo ever in any real danger of being tortured. Finocchiaro has examined this question in some detail (see see “Myth 8 – That Galileo was Imprisoned and Tortured for Advocating Copernicanism” in Galileo Goes to Jail and Other Myths about Science and Religion, ed. R. Numbers, Harvard, 2009, pp. 68-79). Drawing on earlier work by von Gebler and Leon Garzend (“Si Galilée pouvait, juridiquement, être torturé”, Revue des questions historiques, 1911–1912) Finocchiaro summarises how Galileo would have been exempt from torture according to several of the accepted rules regarding its application. Generally speaking, exemptions from torture were made for children (typically defined as under 14) the elderly (over 60), pregnant women or those who had given birth within 40 days, the sick and those who were mute or deemed insane. As Finocchiaro notes, Galileo fell into at least two of those categories, being 69 years old, recently very sick and “suffered from arthritis and a hernia” (Fiocchario, Galileo Goes to Jail, p. 77)

In addition, clergy had exemptions from torture and Galileo was, technically, a clergyman himself. As a mark of favour to Galileo, Pope Urban granted ecclesiastical benefices – granting funds from a canonry in Pisa and another in Brescia – to Galileo’s son Vincenzo in 1627. Because this required swearing a form of Holy Orders and receiving the tonsure – the ritual shaving of the top of a clergyman’s head – Vincenzo declined. So on April 5, 1631, Galileo himself went through that ritual and received the financial benefit. While this did not give him the status of a priest of deacon, it did give him a degree of legal protection for clerics under canon law and made him exempt from many secular legal strictures. So he would have had the legal protection of clerical status when it came to torture by the Inquisition.

But, as Finocchiaro notes, there were ways around these protections and exceptions could be made. Clerics could not be tortured by the secular arm at the Inquisition’s instruction, as was the normal practice, but they could be tortured by other clerics; even if this was very rarely done. Similarly, the other exemptions could also be overruled. In his analysis, Thomas F. Mayer also discusses the ways these exemptions were either less clear than Garzend argued or could be circumvented. He even notes ways Galileo could, technically, have actually qualified for torture, but concludes “Urban may after all have gone easier on Galileo
than the law demanded.” (see Mayer, The Roman Inquisition: Trying Galileo, University of Pennsylvania Press, 2015, p. 205) Overall, Finocchiaro concludes:

“[The June 21] deposition leaves no doubt that Galileo was threatened with torture …. But there is no evidence that he was actually tortured, or that his accusers planned actually to torture him.” (Finocchiaro, Galileo Goes to Jail, p. 76)

After all, Galileo insisted that he did not intend to defend Copernicanism even after the threat of torture and, despite this insistence, no torture was applied. It seems the threat of torture was the limit Urban was prepared to go to so as to obtain the admission he sought and, when Galileo did not give it, that was where things were left.

The irony here is that the mythological version of the story has Galileo being threatened with torture for saying he accepted Copernican heliocentrism. In fact, the only threat of torture was made in response to his repeated insistence he accepted Ptolemaic geocentrism. The myth, yet again, gets things backwards.

(iv) The Sentence and Aftermath

The following day, 22 June, Galileo entered a room adjoining the church of Santa Maria sopra Minerva for the final verdict in his trial. In attendance were seven of the ten cardinal-judges of the Inquisition, as well as Father Vincenzo Maculano, his assistant prosecutor, Father Carlo Sinceri and at least one notary. The verdict was presented as that of the cardinals collectively, but was most likely read aloud by Maculano.

It began by setting out the context of the 1616 ruling on heliocentrism and Galileo’s audience with Bellarmine on 26 February of that year where that ruling had been made clear to him:

That the Sun is the center of the world and motionless is a proposition which is philosophically absurd and false, and formally heretical, for being explicitly contrary to Holy Scripture;
That the Earth is neither the center of the world nor motionless but moves even with diurnal motion is philosophically equally absurd and false, and theologically at least erroneous in the Faith. (Finocchiaro, Documentary History, p. 288)

The verdict went on to detail how Bellarmine had ordered Galileo “to abandon this doctrine, not to teach it to others, not to defend it, and not to treat of it” and how Galileo had sworn to do as ordered and to “neither hold, nor defend, nor teach it in any way whatever, either orally or in writing.” It went on to note the publication of the Dialogue and how this book “was diligently examined and found to violate explicitly the above-mentioned injunction given to you.” In his interrogation, the verdict went on:

You confessed that about ten or twelve years ago, after having been given the injunction mentioned above, you began writing the said book, and that then you asked for permission to print it without explaining to those who gave you such permission that you were under the injunction of not holding, defending, or teaching such a doctrine in any way whatever. (Finocchiaro, Documentary History, p. 289)

Galileo’s defence that he had forgotten the more stringent terms of the 1616 injunction was given short shrift in the verdict. Referring to Galileo’s certificate of May 26 1616, the verdict notes:

Because this certificate does not contain the two phrases of the injunction, namely ”to teach” and “in any way whatever,” one is supposed to believe that in the course of fourteen or sixteen years you had lost any recollection of them, and that for this same reason you had been silent about the injunction when you applied for the license to publish the book. (Finocchiaro, Documentary History, p. 290)

The previous day’s “rigorous examination” was noted, but the verdict assessed Galileo had “answered in a Catholic manner, though without prejudice to the above-mentioned matters confessed by you and deduced against you about your intention.” So then came the verdict’s ultimate findings:

We say, pronounce, sentence, and declare that you …. have rendered yourself according to this Holy Office vehemently suspected of heresy …. Consequently you have incurred all the censures and penalties imposed and promulgated by the sacred canons and all particular and general laws against such delinquents. We are willing to absolve you from them provided that first, with a sincere heart and unfeigned faith, in front of us you abjure, curse, and detest the above-mentioned errors and heresies …. in the manner and form we will prescribe to you. (Finocchiaro, Documentary History, p. 291)

Galileo then read aloud and signed the formal abjuration document given to him (found here, with the verdict). The sentence was then given:

We condemn you to formal imprisonment in this Holy Office at our pleasure. As a salutary penance we impose on you to recite the seven penitential Psalms once a week for the next three years. And we reserve the authority to moderate, change, or condone wholly or in part the above-mentioned penalties and penances. (Finocchiaro, Documentary History, p. 291)

There are several things to note here. Firstly, the verdict uses the same language regarding the basis for the 1616 theological ruling on heliocentrism as the 1615 assessment for the Inquisition: noting both the scientific consensus (“philosophically absurd and false”; “philosophically equally absurd and false”) as well as the theological basis (“explicitly contrary to Holy Scripture”; “erroneous in the Faith”). Once again, the scientific consensus is given the primary position in this formulation.

Secondly, nothing is said about the strength or validity of Galileo’s scientific arguments, since the whole verdict, like the whole case, centres on the 1616 injunction to Galileo and whether he violated it. This was what he was on trial for.

Finally, Galileo was not found guilty of heresy. The verdict was he was guilty of being “vehemently suspected of heresy”. Since most modern readers do not understand the technical language here, they mistake this for a finding of heresy. It is not. As with most things regarding the operations of the Inquisitions and of Catholic theologians generally, there was a hierarchy of degrees of theological error, with the most serious – formal heresy – at the top. “Vehement suspicion of heresy” sat above “light suspicion” but below “violent suspicion”, with all three below “formal heresy” proper (see Mayer, The Roman Inquisition: Trying Galileo, p. 208-9 for definitions and discussion). This is significant because, while someone convicted of formal heresy could potentially, in some circumstances, be sentenced to execution, no-one was ever executed for mere “vehement suspicion”. Originally, it was a catch-all category for those who, while never expressing heretical views themselves, associated with, fed or sheltered heretics. By Galileo’s time it had become a general category for a wide range of lesser theologically dubious or condemned views.

The strongest sentence given for “vehement suspicion” was life imprisonment, which is what Galileo was duly given. This was surprisingly harsh, but the sentence was quietly commuted to house arrest the next day. The verdict and original sentence was widely publicised and copies were circulated through Italy and beyond, while the commutation to a much more lenient punishment, on the other hand, was made quietly. This fits the general pattern noted by Miller (“The Thirty Years War and the Galileo Affair”, see above and particularly p. 64), where the public elements of the trial gave Pope Urban the full political benefits he wanted in the context of his troubles with the Spanish, while the private realities were far more lenient.

So as late as 1728 Voltaire wrote inaccurately of how Galileo “groaned away his days in the dungeons of the Inquisition”, where in fact Galileo never saw the inside of any dungeons at all. Another persistent myth is the idea that after his abjuration Galileo was heard to mutter “Eppur si muove!” (And yet it moves!). This detail fits the mythological depiction of Galileo as the defiant hero, but it is not supported by any evidence from the time or even in the more laudatory early biographies of Galileo, such as that by his disciple Vincenzo Viviani (written 1655–56). It also does not fit the evidence of the time regarding Galileo’s mood and reactions, which appear far from defiant. The story first appears in 1757, as an anecdote by the Italian-born London writer Giuseppe Baretti in his book The Italian Library, and is clearly an eighteenth century invention.

Some writers note that three of the Inquisition’s ten cardinal-judges did not sign the verdict; namely Caspar Borgia, Laudivio Zacchia and Francesco Barberini. Given that Barberini was friendly toward Galileo, it is sometimes surmised from this that these men did not approve of the sentence. However, Francesco Beretta has published a letter from Cardinal Barberini to the Papal Nuncio in Madrid, Cesare Monti, indicating he and Cardinal Borgia were in an audience with Pope Urban on 22 June and so could not have been at Galileo’s condemnation. The same letter notes the example of Galileo as an unfortunate “oversight of those responsible for reviewing books” and his condemnation as evidence Pope Urban was strict in such matters – indicating that placating the Spanish was a key motivation for the whole trial (see Beretta, “Urbain VIII protagoniste de la condamnation de Galilée” in Largo campo di filosofare: Eurosymposium Galileo 2001, José Montesinos and Carlos Solís (eds.), 549–574. La Orotava: Fundación Canaria Orotava de Historia de la Ciencia, 2001, p. 568, n. 98 and Appendix B).

Maculano’s letter to Cardinal Barberini of April 28 1633 mentions “imprisonment in his [Galileo’s] own house” as something that was already being discussed as the likely final sentence months before the verdict, so it seems this was always the likely outcome of the trial. Far from groaning in any dungeons, Galileo began his house arrest first at the Villa Medici once more, and then in the home of his friend Archbishop Ascanio Piccolomini in Siena. There he was treated as an honoured guest, with the Archbishop inviting scholars to dine with them and encouraged lively conversation. This attracted attention, so Galileo was moved to his villa in Arcetri, outside Florence. He could visit his daughters at the nearby Poor Clares convent of San Matteo and could attend mass and confession at nearby churches on feast days. Later, as his health further deteriorated, he was allowed to move into Florance to be closer to his doctors.

During this period Galileo’s visitors and guests were restricted, though with varying enforcement and these restrictions became more lax as he grew more aged and infirm. He was joined by the young mathematician Vincenzo Viviani in 1639, who became his first biographer and his companion in his final years. Galileo continued his scientific work and produced his final book, Discourses and Mathematical Demonstrations Relating to Two New Sciences (1638); a work on the physics of motion that was to become his greatest contribution to science. To avoid the ban on Galileo’s works and published in the Netherlands by the Protestant publisher, Lodewijk Elzevir, who visited Galileo in Arcetri in 1636, receiving the manuscript of the book from him there. Like the Dialogue, the Two New Sciences was presented as a discussion and debate between the characters of Simplicio, Sagredo, and Salviati, though it toned down Simplicio’s conservative Aristotelianism. No Italian editions of the book were published, but the Church seems to have generally turned a blind eye to its sale. In January 1639 Castelli wrote to Galileo to report that both he and Cardinal Barberini had received copies and that the 50 copies available for sale in Rome had quickly sold out.

Galileo’s health continued to deteriorate over the next few years and he and Viviani were joined by the physicist Evangelista Torricelli and his son Vincenzo at Arcetri in his final months, before Gaileo died on January 8 1642 at the age of 77.

“The Catholic Church only finally admitted Galileo was right in 1992.” – The Church continued to reject the science behind heliocentrism until 1992, when Pope John Paul II admitted Galileo was right for the first time, apologised to him and pardoned him.

The idea that the Catholic Church maintained its stance on heliocentrism until 1992 is another popular myth that often forms a smirking coda to popular tellings of the mythological version of the Galileo story. Christopher Hitchens, in the 2009 debate mentioned above, gets laughs from the audience by noting many sins that the Church had recently been forced to acknowledge. He included:

… the admission that Galileo was right [pause for audience laughter] about the relationship between the Sun and the Earth in other orbs which came in 1992. One might say … and I won’t say it, it’s too easy to say … better late than never.

That this acknowledgement included an apology to Galileo by John Paul II is a common elements in this story, and it often also includes claims of an official pardon or a formal lifting of an excommunication of Galileo, despite him never having been excommunicated in the first place. These stories all form a satifying ending to the story, with a humiliating and amusingly belated capitulation by the Church and total vindication of the heroic Galileo.

In fact, this story is mostly fantasy. As Finocchiaro details exhaustively in his magisterial work Retrying Galileo, 1633–1992, (University of California Press, 2005), the rehabilitation of Galileo was actually a slow process of centuries, not a sudden announcement in 1992. For a far less comprehensive but still detailed account of this, see Did the Pope Apologise to Galileo? But, in summary, the Church acknowledged and accepted heliocentrism in 1751 when it removed its general prohibition on books teaching the Earth’s motion and the Sun’s immobility, not in 1992.

The scientific consensus was against heliocentrism throughout all of the key dates of the Galileo Affair and this continued to be the case long after Galileo’s death. As noted above, Giovanni Riccioli’s massive Almagestum Novum assessed the arguments for and against the Ptolemaic, Copernican and Tychonian model and came down in favour of the latter as late as 1651. Of course, like Galileo, Riccioli did not consider Kepler’s model to be worth consideration, but in the following decades this began to change.

Kepler’s Astronomia nova (1609), the book in which he laid out his model, was a difficult and esoteric work even by the standards of early seventeenth century astronomy. His model faced the standard objections against heliocentrism generally, but was also unique in proposing elliptical orbits; an idea considered difficult to accept for two main reasons. All its competitors reained the ancient Greco-Roman idea that the cosmos should be made up of the most elegant and perfect geometric forms: circles and spheres. This was a largely aesthetic and philosophical bias, but so well-entrenched that it was difficult to overcome. More significantly, Kepler did not provide a basis for his orbits in physics which, taken with its other problems, meant Kepler was largely (though not entirely) ignored.

This began to change in 1627, when Kepler published his Rudolphine Tables. These were based on the very precise observational data made by Tycho Brahe and his team, and so became more widely used than the much less accurate alternatives, such as the old Alphonsine Tables or the newer but still inaccurate Prutenic Tables. Their successful use in the prediction and observation of the transit of Mercury in 1631 and the transit of Venus in 1639 added to a growing idea that they worked so well because Kepler’s underlying model was actually correct. Most astronomers accepted this or at least greatly lessened their resistance to the Keplerian model as the seventeenth century progressed, but it was Newton’s Principia Mathematica (1687) that gave a basis for the model in physics and provided a synthesis that showed Kepler had been right. Bradley’s observation of a stellar aberration in 1727 then provided the astronomical proof of the motion of the Earth, confirming heliocentrism scientifically – a full 94 years after Galileo’s trial.

As the consensus against heliocentrism changed over the course of the second half of the seventeenth century, there were early pleas for a reversal by the Church of its bans on heliocentric books and on the works of Galileo. As early as 1665 the French astronomer, Adrien Auzout, made the case that “this hypothesis [heliocentrism] is neither absurd nor false in philosophy, as one believed at first; nor is it in any way prejudicial to the Faith” (Finocchiaro, Retrying Galileo, p. 95). His appeals failed, but in 1718 Tommaso Bonaventura and Dom Guido Grandi gained permission to publish a three volume edition of Galileo’s works, minus his Dialogue. Then in 1753 Pope Benedict XIV issued a bull, Sollicita ac Provida, on reform of the Index Prohibitorum, which resulted in the general prohibition against heliocentric works being dropped from the Index in 1757. This was 28 years after Bradley’s publication of his proof of the motion of the Earth, which is, by the standards of the ponderous workings of the Vatican, remarkably speedy.

Prohibitions against five specific works, including Kepler’s Epitome of Copernican Astronomy (1618-21) and, of course, Galileo’s Dialogue, stayed in place, however. This remained the case for a further 63 years until the oddity known as the Settele Affair brought things to a conclusion. In 1820, a Roman professor called Giuseppe Settele sought an imprimatur for the second volume of his science textbook and expected no problems with its being granted. But the the Master of the Sacred Palace, the Dominican priest Filippo Anfossi, refused on the grounds it assumed the motion of the Earth, to the great surprise of most involved. Settele consulted two Inquisitors and then appealed to Pope Pius VII, who referred the matter to the Inquisition in March 1820. This resulted in the ironic situation where the Holy Office of the Inquisition, the very body that had condemned Galileo 187 years earlier, now argued rigorously for heliocentrism. The whole affair was largely a petty Vatican turf war over authority and hierarchy, but the European press had a field day with it and it led to the final dropping of all prohibitions on the subject by  Gregory XVI on 20 May 1833. The new edition of the Index Prohibitorum in 1835 simply no longer had any bans on relevant works, including Galileo’s Dialogue.

Of course, this was all done without great fanfare or any public announcement or acknowledgement. Contrary to the myth above, that did not actually come in 1992, but rather in 1979. Pope John Paul II was elected in 1978 and was a new pope who was both a conservative and a reformer. Like many more conservative prelates, he thought some of the great reforms of the Second Vatican Council (1962-65) had been too rapid, and he sought to shore up the place of the Catholic Church in a fast changing world. As part of this, in 1979 he used the occasion of the centennial of the birth of Albert Einstein to speak on the Galileo Affair and reflect on its place in the history of the relationship between science and the Church. In his speech (10 November 1979), he spoke of how Galileo “had to suffer a great deal at the hands of men and organisms of the Church” and announced his commission of a stundy into the Affair by the the Pontifical Academy of Sciences. This was the first public acknowledgement any wrong against Galileo, though it went virtually unnoticed by the media.

The resulting Papal Commission worked on and off on the project of examining the Galileo Affair from historical, theological and scientific perspectives for the next 13 years, with the Pope receiving its final report on 31 October 1992. This was the occasion of the speech by Pope John Paul that actually did attract media attention and resulted in the “apology/pardon” myth.

Again, as detailed elsewhere (see Did the Pope Apologise to Galileo?), there was no apology in the speech and certainly no pardon. The speech was actually fairly dense and aimed at the members of the Papal Commission, so it assumed a lot of prior knowledge of the relevant history and theology – all things the journalists present largely lacked. The speech was also a smooth piece of revisionisn, with the Pope referring with careful vagueness to “Galileo’s judges”, his unnamed “adversaries”, and to “the majority of theologians”; all without pointing the finger at anyone in particular. This deftly stepped around the fact that these “adversaries” were the Inquisition and Pope John Paul’s own predecessor, Urban VIII. So it neatly paints the affair as “a tragic mutual incomprehension.”

All this complexity and subtlety appears to have been lost on the English language journalists present, so they filed stories that presented a much neater version of events: “the Pope has finally admitted Galileo was right”. This ignores the 1979 speech and all of the rehabilitation process back to 1757. But it made for a better story and better jokes. From there, the stories of pardons and lifting of excommunication invented themselves.

This final episode in the long story of the Galileo Affair is typical of the way the history has evolved into myth. Popular accounts that distort the complexities of the case give rise to simplistic but narratively satifying myths that take immense work to correct with the evidence to tell the real story. This is why the mythological version of the Galileo Affair is likely to always trump any historical correction. Myths are easy. History is hard.

Bibliogrphy

Francesco Beretta, “Urbain VIII protagoniste de la condamnation de Galilée” in Largo campo di filosofare: Eurosymposium Galileo 2001, José Montesinos and Carlos Solís (eds.), 549–574. La Orotava: Fundación Canaria Orotava de Historia de la Ciencia, 2001

Mario Biagioli, Galileo, Courtier: the Practice of Science in the Culture of Absolutism, University of Chicago Press, 1993

Richard J. Blackwell, Galileo, Bellarmine and the Bible, University of Notre Dame Press, 1991

Annibale Fantoli, Galileo: For Copernicanism and for the Church, trans. G.V. Coyne, Vatican Observatory Publications, 1994

Maurice Finocchiaro, The Galileo Affair: A Documentary History, University of California Press, 1989

Maurice Finocchiaro, Retrying Galileo, 1633–1992, (University of California Press, 2005

Maurice Finocchiaro, The Essential Galileo, Hackett, 2009

Maurice Finocchiaro, “Myth 8 – That Galileo was Imprisoned and Tortured for Advocating Copernicanism” in Galileo Goes to Jail and Other Myths about Science and Religion, ed. R. Numbers, Harvard, 2009, pp. 68-79

Maurice Finocchiaro, “Authenticity vs. Accuracy vs. Legitimacy: Pagano on the Vatican Documents” in Science, Method, and Argument in Galileo, vol. 40, Cham: Springer, 2021, pp. 337–353

Karl von Gebler, Galileo Galilei and the Roman Curia, George Sturge (trans.), Kegan Paul, 1879

Owen Gingerich, The Book Nobody Read: Chasing the Revolutions of Nicolaus Copernicus, Walker, 2004

Christopher Graney, “The Inquisition on Copernicus, February 24, 1616: A Little Story About Punctuation”, 2016

Christopher M. Graney, Setting Aside All Authority: Giovanni Battista Riccioli and the Science against Copernicus in the Age of Galileo, University of Notre Dame Press, 2022

Henry Ansgar Kelly, “Galileo’s Non-Trial (1616), Pre-Trial (1632–1633), and Trial (May 10, 1633): A Review of Procedure, Featuring Routine Violations of the Forum of Conscience”, Church History, 2016, 85(4), pp. 724-76

Thomas F. Mayer, ed., The Trial of Galileo, 1612–1633: A Documentary Edition, University of Toronto Press, 2012

Thomas F. Mayer, The Roman Inquisition: Trying Galileo, University of Pennsylvania Press, 2015

D.M. Miller, “The Thirty Years War and the Galileo Affair”, History of Science, 46 (1), pp.49-74

Pietro Daniel Omodeo, Copernicus in the Cultural Debates of the Renaissance: Reception, Legacy, Transformation, Brill, History of Science and Medicine Library / Medieval and Early Modern Science, 23, 45, 2014

Ada Palmer, Inventing the Renaissance: Myths of a Golden Age, Bloomsbury, 2020

Olaf Pedersen, “Galileo’s Religion”, The Galileo Affair: A Meeting of Faith and Science: Proceedings of the Cracow Conference, May 24-27, 1984, Citta del Vaticano: Specola Vaticana, 1985, edited by Coyne, G.V., pp.75-102

William R. Shea and Marianoa Artigas, Galileo in Rome, Oxford University Press, 2003

Robert S. Westman, , “The Astronomer’s Role in the Sixteenth Century: A Preliminary Study,” History of Science, 18 (1980): 105-147

Emil Wohlwill, (Der Inquisitionsprocess des Galileo Galilei: Eine Prüfung seiner rechtlichen Grundlage nach den Acten der Römischen Inquisition, Hamburg, 1870