List of Scientists Executed by the Catholic Church

Those who say that the Catholic religion is intrinsically hostile to scientific inquiry will often have recourse to stories about the Catholic Church’s repression of scientific activities, specifically regarding the Church’s alleged persecution of scientists for their scientific theories. The case of Galileo is well known and was documented (though woefully misunderstood), but there are several others that merit study as well. In this essay, we will examine the lives of ten scientists who somehow came into conflict with the Church. We will examine the circumstances of their condemnations and see if the accusation that the Church punished people for their scientific beliefs holds merit. In each case, myth will be contrasted with history to give a balanced picture of what happened.


Hypatia was a pagan philosopher in late 4th century Alexandria. She appears to have been a lecturer in Platonic thought, a practicing scientist, and the author of several mathematical treatises. She was killed by a Christian mob in the year 415.

Myth: In an age when a male-dominated Christian clergy was working to suppress independent thought, Hypatia served as a walking affront to clerical power. As an important scientist, a pagan—and most annoyingly, a female—Hypatia’s very existence was a threat to the social order imposed by the Christian clergy. When speaking publicly in favor of religious toleration, she was seized by an angry Christian mob and murdered, with the enthusiastic support of the local Christian bishop, who found it intolerable that Christians should be lectured by a scientist and a woman.

History: Hypatia’s death was political. In 415, the city of Alexandria was in tumult due to a row between Orestes, the Roman governor, and St. Cyril of Alexandria, the city’s bishop. Orestes coveted the growing power of the Christian bishop and sought to undermine St. Cyril’s authority by instigating the city’s sizable Jewish population to violence against the Christians. After a violent night-time slaughter of Christians at Jewish hands, Cyril struck back by securing the exile of many of Alexandria’s Jews, including some wealthy patrons of the governor. Orestes employed the noted pagan philosopher Hypatia to negotiate peace with St. Cyril. Hypatia was not an enemy of Christianity; on the contrary, she was respected by the Christian intellectual circles of the day. She maintained correspondence with Bishop Synesius of Cyrene, with whom she discussed scientific theories, and she was well respected by the Church historian Socrates Scholasticus. The local Christian populace, however, was suspicious of her intervention because she was a pagan and Orestes had proven untrustworthy in the past. Fearing another ambush was being planned, as had occurred at the hands of the Jews, they apprehended Hypatia and killed her. The historian Socrates, who was a contemporary of the events, stated that the cause of her death was political, that she was a “victim to the political jealousy which at the time prevailed.”[1] She was not killed for being a scientist, much less a woman. Other persons had been similarly killed in the same conflict for similar reasons who were neither scientists nor female.

Furthermore, the Church did not instigate nor celebrate her death. St. Cyril denounced the ruthless murder of Hypatia, and Socrates, the Catholic historian of the era, wrote, “Surely nothing can be farther from the spirit of Christianity than the allowance of massacres, fights, and transactions of that sort.”[2]

Roger Bacon

Roger Bacon (1220-1292) was an English philosopher and Franciscan friar who was a talented natural scientist. He is considered one of the pioneers of the scientific method and was noted for his use of empirical observation. His greatest work was the Opus Major, which contains treatments of mathematics, optics, alchemy, and astronomy, including theories on the positions and sizes of the celestial bodies. Bacon may have been imprisoned by ecclesiastical authorities in 1279 and there is a tradition that he died in captivity.

Myth: Bacon was one of the great freethinkers of the Middle Ages. Criticizing everything from Scholasticism to the Julian Calendar to the acceptance of Catholic doctrine on the authority of the Church and tradition, Bacon aroused the ire of the ecclesiastical regime. He was imprisoned in 1279 for being too free in his hypotheses and spent the rest of his life forcibly confined in a Franciscan monastery under the orders of Franciscan Minister-General Jerome of Ascoli, where he eventually died in captivity, a medieval martyr to free thought.

History: Details on Bacon’s life are thin, but he was certainly not persecuted for his scientific ideas. Roger Bacon was a friend of Pope Clement IV. He sent the pope a copy of his Opus Major, which the pope received joyfully. Clement IV also received copies of Bacon’s scientific treatises Opus Minus, De Multiplicatione Specierum, and De Speculis Comburentibus, as well as an optical lens Bacon had been working on. None of these works were censured by the pope or any other clerical authority. Bacon did get in trouble in 1277, not for his scientific theories, but because he had slandered other professors and monks in his 1271 Compendium Studii Philosophiae. This alone might not have been sufficient to put him in danger, but he had also aligned himself with the radical Franciscan Fraticelli in the debate between the Spirituals and the Conventuals. The Minister-General of the Order, Jerome of Ascoli, thus used the opportunity to crack down on a trouble-maker within the order. Bacon also had a reputation as a theological loose cannon because of his promotion of certain wild prophecies then floating around in relation to the Spiritual-Conventual debate, as well as his preference for deterministic astrology. Most historians reject the idea that Bacon was persecuted for any scientific theory.[3] Records of his captivity only note he was imprisoned for “suspected novelties.”

It is uncertain, however, whether Bacon ever was actually imprisoned. The first reference to Bacon’s alleged imprisonment does not appear until almost eighty years after his death. There is no contemporary evidence that Bacon was ever imprisoned, let alone that he died under house arrest.

The Story of Medieval Wizard Roger Bacon - WorldAtlas
Roger Bacon (1219-1292)

Pietro d’ Abano

Pietro d’ Abano (1257-1316) was an Italian philosopher, astrologer, and professor of medicine. He was a renowned author whose most famous work was Conciliator Differentiarum, quæ inter Philosophos et Medicos Versantur, an exploration on the relationship between contemporary medical theories and Aristotelian natural philosophy. He was arrested by the Inquisition and died in prison around 1316. He was condemned posthumously, and his bones burned.

Myth. The myth is that Abano was such an educated man that Church authorities assumed he must be in league with the devil. He was accused of witchcraft and of obtaining his knowledge by the dark arts, which was a common accusation made against learned people. Abano is lucky he died in prison or else he certainly would have been burned alive.

History. The truth is less dramatic but more interesting. As discussed above, medieval science was often bound up with occultic practices and magic. Though Abano was a distinguished physician and scholar, he was also deeply involved in the occult. He practiced geomancy (earth divination) and appears to have observed some primitive form of phrenology—the idea that the inner character of a person could be discerned by the shape of their skull. Abano also dabbled in palmistry and was apparently so engaged in the dark arts that he wrote a magical tome called the Heptameron, a book of occultic rituals for conjuring specific angels for the seven days of the week. His arrest by the Inquisition seems to be on the grounds of magic and his astrological theories, for he apparently taught that natural effects were produced by celestial bodies and the arrangements of the stars. Abano cannot be considered to have suffered for science unless one is ready to admit palmistry, conjuring, geomancy, and astrology as scientific doctrines.

Cecco d’ Ascoli

Cecco d’ Ascoli (1257-1327) was an Italian encyclopaedist, physician, and scholar specializing in mathematics and astronomy. He was a professor of astronomy at the University of Bologna and was such a noted astronomer that there is a crater on the moon named after him. He is famous for his feud with the poet Dante. He was eventually tried for heresy and burned at the stake in Florence, the first university professor to be condemned to death by the Inquisition.

Myth. Like Bacon, myths surround the legacy of Ascoli. The popular narrative posits Ascoli as a troublemaking freethinker who eschewed Church doctrine in favor of scientific facts.  His death at the stake in 1327 as an example that university professors could not be too assertive in promoting scientific theory.

History. The truth is that Ascoli fell afoul of the Inquisition, not for any scientific work, but for some wild theories regarding demonology he made in a commentary on John de Sacrobosco’s book The Sphere of the Cosmos. Ascoli fled the papal court to Florence where he subsequently got in trouble for trying to read Christ’s horoscope. He had already incurred the enmity of the eminent physician Gino del Garbo, who had formerly accused Ascoli of plagiarism. Seeing Ascoli again in trouble, Garbo hounded Ascoli until he secured his condemnation for impiety for his demonological theories and the incident with the horoscope. Ascoli was subsequently condemned and burned. Again, it was not for his scientific theory that Cecci d’Ascoli was put to death, but for his occultic impiety exacerbated by the jealousy of a professional opponent.

Michael Servetus

Michael Servetus (1509-1553), usually known simply as Servetus, was a Spanish doctor, theologian, mapmaker, and Humanist scholar. His expertise spanned many areas; he wrote treatises in mathematics, astronomy, meteorology, geography, human anatomy, medicine, and pharmacology, as well as jurisprudence and poetry. In 1553 he was tried and sentenced to death in Vienna by the Inquisition, though it would ultimately be the Calvinists who put him to death in Geneva later that year.

Myth: The intransigent Catholic authorities in Vienne (and the Calvinists of Geneva) could not tolerate the challenge posed to their respective creeds by the scientifically minded Servetus. Rather than deal with his skeptical arguments rationally, it was easier to off Servetus by burning him at the stake, thus making Michael Servetus a true martyr to science.

History: Servetus was not a religious skeptic. Servetus denied the tenets of both the Catholic and Protestant creeds, but not because of religious skepticism per se, but because he was a Unitarian—he rejected the doctrine of the Holy Trinity. Servetus believed that the doctrine of the Trinity represented a pagan corruption introduced into the Christian faith via the Greek philosophers. He hoped his ideas would help purify Christianity, as he argued in his 1553 books Restoration of Christianity. It was for his heterodoxy regarding the Trinity that he was condemned by the Inquisition and later burned at the stake by John Calvin. He was certainly not killed for any of his scientific ideas.

The Execution of Michael Servetus & My Primary Deal-Breaker with Calvinism  - Benjamin L. Corey
The execution of Michael Servetus in 1553 in Champel, Switzerland

Girolamo Cardano

Girolamo Cardano (1501-1576) was a Renaissance polymath whose talents ranged from mathematics to medicine, biology, physics, chemistry, astronomy, philosophy, and linguistics. He was one of the most influential mathematicians of the Renaissance and was one of the key figures in the foundation of probability and the earliest user of the binomial coefficients and the binomial theorem in the west. He wrote over 200 scientific treatises. Cardano was arrested and condemned by the Inquisition and spent several years imprisoned, though he was eventually released and rehabilitated by Pope Gregory XIII. He is famous for his contributions to algebra and made the first systematic use of negative numbers.  

Myth: Cardano was a rationalist who was unfortunate enough to live and teach during the reforms of the Council of Trent. His originality and natural inquisitiveness got him in trouble with the Inquisition, who forced him to resign his professorship and imprisoned him. If it were not for friends in high places, he would have been burned as a heretic.

History: Cardano possessed an extremely abrasive personality that brought him into conflict with his professional peers. He was disliked at the University of Pavia, where he taught. During this period, his sons brought him much shame. His elder son Giovanni was tried and beheaded for murdering his wife; his younger son Aldo was a gambler and a profligate who was disinherited by Cardano. Cardano always suspected his elder son’s execution was pushed by his professional rivals and fled Pavia, not only due to professional difficulties but to allegations of sexual impropriety with students. The Inquisition arrested him in 1570, but he was imprisoned only very briefly. He was released upon renouncing his professorship, which seems to have been the aim of his enemies. After his release, he was employed by Gregory XIII and given a lifetime annuity to compensate him for his difficulties. It is evident that Cardano’s arrest by the Inquisition was a strong-arm tactic employed by his professional rivals to secure his resignation. He never seems to have been in danger of his life and there is no indication his scientific theories were ever the reason for his persecution.

Giordano Bruno

Bruno is among the most famous scientists ever to run afoul of the Inquisition. Giordano Bruno (1548-1600) was a Dominican friar, mathematician, astronomer, and poet. He is most remembered for his cosmological theories. After seven years of trials in Rome, he was condemned and burned at the stake in 1600.

Myth: Like Galileo, Bruno’s great crime was proposing that the earth was not stationary at the center of the universe. He proposed that stars were like other suns, each of which might have their own exoplanets capable of supporting life. This ran counter to Church doctrine, so the Inquisition had him executed for having the audacity to challenge Catholic dogma. He was burned at the stake, a martyr to science.

History: Bruno’s case is difficult because it is unknown to what degree his cosmological theories were behind his condemnation. Beginning with the advent of agnostic rationalism in the 18th and 19th centuries, historians were anxious to make Bruno into a martyr for science. It is true that he was burned at the stake in Rome in 1600, but the church authorities guilty of this action were almost certainly more distressed at his denial of Christ’s divinity and his other heresies than his cosmological doctrines. [4] Many documents of his trial have been lost, but a summary of the proceedings against Bruno still exists. The summary lists eight charges against him; of the eight charges, only one relates to his cosmological theories, and even this charge seems to relate to a philosophical rather than scientific problem. Bruno believed the universe was infinite in size and contained an infinite amount of other habitable planets. His assertion of the infinitude of the universe called into question the theological truth of the universe as a creation, as only God is infinite in the proper sense. Nothing created can be infinite.

Whatever we think about this idea, this was not a scientific theory. Galileo would not invent the first proper telescope until nine years after Bruno’s death, so enhanced empirical observation of space had not yet begun. Bruno’s theorem was not a scientific idea based on observation; it was a philosophical assumption about the nature of the universe that is more properly understood against the backdrop of earlier medieval philosophical debates about the eternity of the world than any hard science. It certainly may have had scientific aspects to it, but maybe it didn’t; we do not know, as the notes of Bruno’s trial have not been preserved.

The other seven charges against Bruno all related to points of theology. He was charged with defaming the ministers of the Church, denying the Trinity, denying the divinity of Christ and the Incarnation, calling the virgin birth into doubt, denying that Jesus was the Messiah, denying Transubstantiation and the sacrificial nature of the Mass, the transmigration of souls, reincarnation of human souls into animals, dealings in magic and divination. The Church authorities were undoubtedly much more concerned with these charges than his theory that other planets could contain some form of life. Recall that Copernicus, a Polish Catholic priest, had also postulated a non-traditional cosmology and yet remained in the good graces of the Church, demonstrating that it was not proposing novel cosmologies alone that got one in trouble. Similarly, Galileo’s troubles began not when he questioned the traditional Ptolemaic cosmology, but when he postulated a new relationship between faith and science that sought to subvert faith beneath empiricism.

While initially willing to accept the Church’s dogmatic positions, Bruno ultimately refused a recantation and died obstinate. His death was due to the theological doctrines he denied, not because of the cosmology he affirmed. His abrasive attitude and arrogance probably exacerbated his troubles. Renaissance historian Mordechai Feingold wrote, “Both admirers and critics of Giordano Bruno basically agree that he was pompous and arrogant, highly valuing his opinions and showing little patience with anyone who even mildly disagreed with him…it might have been Bruno’s manner, his language and his self-assertiveness, rather than his ideas that caused offense.”[5]  Nor were Bruno’s ideas necessarily scientific; some historians, rejecting the “martyr of science” view as a 19th century myth, see Bruno’s cosmology as retrograde. Modern historian Frances Yates notes, “Bruno pushes Copernicus’ scientific work back into a prescientific stage, back into Hermetism, interpreting the Copernican diagram as a hieroglyph of divine mysteries.”[6]

At any rate, the “martyr to science” view of Bruno is much too simplistic. He was executed for his heresies, not his cosmology.

Lucilio Vanini

Philosopher and physician Lucilio Vanini (1585-1616) was a Carmelite and notable scholar of the late Renaissance. He was a libertine, political opponent of the popes, and known as an early proponent of some form of evolution from primates. He once left the Church for Anglicanism but later returned to the faith. He went through a period of itinerant wandering, where he seemed to always get in trouble with the authorities. He eventually adopted a false identity and died under circumstances that are still uncertain in 1619, executed for blasphemy and heresy by the authorities in Toulouse. He was strangled, had his tongue removed, and his body burned.

Myth: Vanini was one of the first eminent naturalists, who attributed supernatural events to human imagination and called out clerical authorities for the charlatans they were. His naturalism put him at odds with the Church authorities, who hounded him from city to city until he was forced to take on a fake identity. Not even this could save him from the rabid Inquisition, who hunted him down and killed him in 1619.

History: Vanini began as a Carmelite friar with doctorates in canon and civil law. He had a reputation as a talented scholar, but he began to get into trouble after 1608 when in Venice he came under the influence of Paolo Sarpi, a fierce opponent of the papacy. It is too much here to go into the minutiae of the diplomatic crisis between Venice and the popes in the early 17th century; it suffices to say Vanini got embroiled in Venetian politics and became a notable anti-clericalist. During this time he also wrote several works denying the immortality of the soul. He was commanded by his superiors to report to Naples for discipline, but instead he fled to England, repudiated the Catholic faith, and became an Anglican in 1612. He soon returned to the faith and became persona non grata in England. Fleeing to France, he unfortunately was caught up in a wave of anti-Italian sentiment that swept the kingdom in 1618-1619. It’s unclear to what degree Vanini was involved in this. At any rate, he took up a false identity and began a period of itinerant wandering through southern France, eventually winding up in Toulouse. The secular authorities in Toulouse were suspicious and interrogated him. The Parlement of Toulouse found Vanini guilty of blasphemy and atheism and put him to death, although it is important to note they did not realize it was Vanini at the time, as he was traveling under a false identity.

The reasons for Vanini’s death are obscure, but a few facts should be pointed out:

First, his death had nothing to do with the Church. It was not the Church, but the secular authorities who apprehended him and the Parlement of Toulouse that condemned him to death, as blasphemy and atheism were civil crimes at the time. The Catholic Church had no part in his death whatsoever.

Second, Vanini could not have been put to death for his scientific theories since the Parlement which condemned him did not know the man they were executing was Vanini.

Third, it’s questionable to what degree Vanini was a dissenting skeptic. Though he once denied the immortality of the soul, he was reconciled with the Catholic Church after his sojourn in England and even wrote a book attacking atheism and affirming the teachings of the Council of Trent. He certainly went through a skeptical phase, but it is a stretch to insist he maintained those opinions until his death. The formal charges against him were blasphemy and atheism, but there is little evidence beyond this. What really happened is uncertain.

Tommaso Campanella

The Dominican friar Tommaso Campanella (1568-1639) was an Italian astrologer, philosopher, and poet. Early in his career he became disenchanted with Aristotelian thought and became a proponent of the new empiricism. He was briefly imprisoned by the Inquisition for engaging in wild astrological speculation. He was released but was apprehended in Calabria, tortured, and spent twenty-six years in prison. He was later released to be part of the court of Pope Urban VIII and had some remote involvement in the Galileo affair. Despite his age, he again got in trouble and had to go into exile to the court of Louis XIII of France, where he died in 1639.

Myth: Campanella was an empiricist who questioned the authority of Aristotle. His skepticism of Aristotle was anathema to the Inquisition, who had Campanella arrested, tortured, and imprisoned for his commitment to empirical science. The bloodthirsty Inquisition would have put Campanella to death had he not feigned madness in his cell.

History: Campanella’s questioning of Aristotle did get him in trouble with the Inquisition, but he was released after only a brief confinement. What got Campanella in trouble was not his science, but his politics. In his hometown of Stilo in Calabria he was a ringleader in a political conspiracy against the Spanish rulers of the city. Inspired by the theories of the 12th century theologian Joachim of Fiore, Campanella hoped to overthrow the Spanish and establish a communist republic with goods, wives, and children held in common. The coup failed; Campanella was tortured and imprisoned. All his most important scientific works were written from prison in Naples. After his release in 1626, he worked for Pope Urban VIII, but continued to advocate for political communism. When one of his followers attempted a coup in Calabria in 1634, Campanella had to flee to France where he lived in exile until his death. Campanella’s torture and imprisonment were due to his radical political activities, not his scientific ideas. Political revolution tends to get one in trouble.

Kazimierz Lyszczynsk

Kazimierz Łyszczyński 

The case of Kazimierz Lyszczynsk (1634-1689) is unique in that he did not have a reputation as a scientist. He was a Polish soldier and nobleman, but also an amateur scholar and philosopher. Lyszczynsk was educated by the Jesuits but later became an opponent of the Society, whom he would oppose as a judge in several cases against the Jesuits concerning ownership of estates. He was arrested and charged with atheism and blasphemy based on a supposed atheist manuscript he had written entitled On the Non-Existence of God. He was condemned and beheaded in 1689 after having his tongue tore out and hands burned.

Myth: At the dawn of the age of reason, Lyszczynsk dared to speak out against the irrational belief in an invisible deity by publishing one of the first Polish treatises examining the world from an atheist perspective. The Catholic Church had him condemned and cruelly executed, a martyr to the atheist cause.

History: It is uncertain whether Lyszczynsk was truly an atheist. Lyszczynsk had a great interest in philosophical problems. Like other philosophers of the age, Lyszczynsk found traditional arguments for the existence of God to be unconvincing. For example, Lyszczynsk read Henry Alsted’s Theologia Naturalis, which attempted to prove the existence of God by arguments from reason. Alsted’s arguments, however, were so confused that Lyszczynsk believed they actually undermined the argument for faith. In his copy of Alsted’s book, Lyszczynsk ridiculed the argument by writing “ergo non est Deus” (“Therefore, God does not exist”) in the margins. It is important to note Lyszczynsk does not appear to have been arguing God did not exist but stating that if Alsted’s weak arguments were followed to their logical conclusions, it would imply the non-existence of God.

Lyszczynsk’s own treatise appears to have proposed proving the existence of God on more solid philosophical grounds. In this sense, he appears like Rene Descartes, professing belief in God’s existence but seeking for a demonstrative rational argument that was philosophically unshakeable. Sometime in 1674, he began work on a treatise that he hoped would provide this philosophical argument. The treatise was structured in the form of a dialogue between an atheist and a Catholic, in which the atheist would make his case for the non-existence of God, followed by the Catholic rebuttal.

At this point, Lyszczynsk got into serious trouble. There was a certain cleric named Jan Brzoska who was the papal nuncio in Brest and an attendant of the royal court. This Brzoska had borrowed a very large sum of money from Lyszczynsk and was without means to pay it back. Brzoska somehow came upon Lyszczynsk’s copy of Alsted’s Theologia Naturalis and found Lyszczynsk’s “ergo non est Deus” scribbled in the margins of the book. He made off with the book and presented it to the Church authorities, accusing Lyszczynsk of atheism and blasphemy. As further evidence, Brzoska also stole Lyszczynsk’s private manuscript he had been working on. This seemed particularly damning, as at the time Brzoska stole the manuscript, Lyszczynsk had only completed the first half of the book, in which the atheist presented his case against God. This section was titled “On the Non-Existence of God.”

Lyszczynsk was in a terrible position. He insisted on his belief in God and explained that his manuscript was incomplete, that the next section was to contain a Catholic rebuttal to the claims of the atheist, that the final title of the work would not be “On the Non-Existence of God”; this was only the title of the atheist’s dialogue. He also said that he had paused work on the manuscript because his confessor had advised him against it.

Unfortunately, Brzoska knew that if Lyszczynsk went free he would have to pay back his large debt. Using his influence as nuncio, Brzorska painted Lyszczynsk as a rabid atheist and was able to secure the support of the entire Polish hierarchy against Lyszczynsk. King Jan Sobieksi attempted to rescue Lyszczynsk by having the case transferred to Vilna, but the clergy, led by Brzoska, insisted on his condemnation. Brzoska succeeded in getting Lyszczynsk condemned to death by the royal diet of 1689. Despite professing his innocence and recanting any errors he may have professed, Lyszczynsk had his tongue tore out, hands burned, and suffered beheading before having his body and his manuscript committed to the flames.

The story of Kazimierz Lyszczynsk is a truly tragic one; the manipulation of canonical and civil law by nuncio Brzoska to secure the condemnation of a person whose guilt was far from certain for the purpose of avoiding a debt is deplorable. But we must keep in mind that Brzoska’s debt does seem to be the motivating factor in Lyszczynsk’s condemnation. If Brzoska had not owed Lyszczynsk a considerable sum of money, it’s unlikely he or any churchman would have been bothered by Lyszczynsk’s philosophical writings. Rene Descartes had undertaken an essentially similar task in France during the same era and was left unmolested. But who knows what would have happened to Descartes had a hostile and powerful clerical opponent got a hold of Meditations on First Philosophy in an incomplete state, when Descartes had undermined the traditional arguments for God’s existence but had not yet presented his own arguments in favor.

Yes, in a technical sense, the death of Lyszczynsk was instigated by the Polish Catholic Church. But the motivating factor was clearly the financial obligations of a corrupt cleric. Lyszczynsk was not a martyr to science or atheism; he arguably was not an atheist at all. Rather, he was the victim of greed and corruption.


In none of these cases was a person put to death or imprisoned merely on account of his or her scientific ideas; in most cases, these people were punished for theological heresies, political activities, or financial reasons. The skeptic might retort that for the Church to seek a man’s condemnation for heresy is just as bad or worse than condemning him for science. The point could certainly be argued, but it is a different argument altogether. The original complaint was that the Catholic Church had executed scientists because of their scientific theories. One may argue that the Church should never have sought punishment for any man’s ideas, scientific, political, or otherwise, but that was not the point in dispute. We are here concerned only with punishment for scientific ideas, and it is clear that the Church did not punish anybody with death merely on account of their scientific beliefs.

It should also be pointed out that in none of these cases did the Church actually kill anybody. In premodern times, heresy was a civil crime in the secular law books. Lyszczynsk was condemned by a secular royal diet; Vanini by the Parlement of Toulouse, and so on. It was the Church’s role to verify that the accused actually professed the heresy of which he was suspected, but it was the secular power that pronounced sentence and executed it. The Church did not execute anybody, scientist or otherwise. Persons guilty of secular crimes were handed over to the secular authorities for punishment according to civil law. It could, of course, be argued that this is mere semantics because the Church was nevertheless complicit in handing them over when they knew they would be punished by the secular authorities. But again, this would be shifting the ground of the argument. We can debate whether heresy should or should not be a secular crime, but our original question was whether the Church had executed people. Clearly the Church did not.

This article appears as the appendix of the book In Pursuit of Wisdom: Science and Catholicism Through the Ages by Phillip Campbell (Our Sunday Visitor: Huntington, IN., 2024).

(1) Novak, Ralph Martin Jr., Christianity and the Roman Empire: Background Texts (Harrisburg, PA: Bloomsbury Publishing, 2010) pp. 239–240

(2) Ibid.

(3) Lindberg, David C., “Medieval Science and Its Religious Context”, Osiris, Vol. 10, No. 10, 1995, pp. 60–79, JSTOR 301913, doi:10.1086/368743.

(4) Michael J. Crowe, The Extraterrestrial Life Debate 1750–1900 (Cambridge University Press: Cambridge, 1986), 10

(5) Feingold, Mordechai, “The occult tradition in the English universities of the Renaissance: A Reassessment,” in Occult and Scientific Mentalities in the Renaissance ed. By Brian Vickers (Cambridge University Press: Cambridge, 1984), pp 73–94

(6) Frances Yates, Giordano Bruno and the Hermetic Tradition (Routledge and Kegan Paul: London, 1964), 225

Phillip Campbell, “List of Scientists Executed by the Catholic Church,” Unam Sanctam Catholicam, Feb. 25, 2024. Available online at