Say the name Galileo, and most people picture the astronomer standing before scowling Inquisition judges, forced to recant his claim that the earth revolves about the sun.

To secular scholars, Galileo Galilei (1564-1642) was a martyr to religious bigotry, demonstrating how pious superstition can shackle human knowledge. To Protestant historians, Galileo's fate is a sharp contrast to the freedom other Enlightenment luminaries, like Robert Boyle, Isaac Newton, and Johannes Kepler, enjoyed in Reformation regions.

But there's more to Galileo's story. Born in 1564 into a Europe passionate—and passionately divided—about its faith, the astronomer experimented, observed, and published his findings without ecclesiastical restraint for almost seventy years before his run-in with the papal authorities. He lived and died just as faithful to the Roman Church as Boyle was to the Anglican or Kepler to his Lutheran roots.

This stands in contrast to the network of thinkers and tinkerers, self-styled "the New Philosophers," who would help bring the scientific revolution to full flower. Many of those men paid little attention to the commitments of nationality or religion that divided their contemporaries. They considered themselves citizens of a borderless and nonsectarian commonwealth of science. Indeed, for some, their allegiance to the pursuit of verifiable truths about the natural world superseded all other commitments. The Dutch mathematician and physicist Christiaan Huygens, for example, declared, "The World is my Fatherland, Science is my Religion."

Despite Galileo's faithfulness to his church, he is most often portrayed today as a secular scientific hero who stood firm against religious bigotry. His loyalty to his faith is largely ignored. Internationally famous by middle age, he might easily have found more intellectual freedom in England or the Dutch states or even in the French court. Yet he remained in Italy and submitted to an Inquisition he considered ignorant and a pope who used him as a political pawn.

Astronomy's new star

Galileo's career launched in 1604, when he demonstrated that a new star, a supernova, was further away than the moon. This may strike the modern reader as fairly obvious, but the cosmological implications for the early seventeenth century were enormous. His study of the new star confirmed his growing belief in a Copernican—heliocentric—universe.

During this same year, Galileo began pursuing a fruitful patronage relationship by buttering up Cosimo II de Médici, who was slated to inherit his father's title as Grand Duke of Tuscany. The struggling academic dedicated one of his new inventions, a geometric and military compass, to Cosimo. Five more years would go by, however, before the old duke obliged his scion (and gave hope to the astronomer) by dying.

Meanwhile, Galileo supplemented his income by selling his newly invented compass to students, along with a handbook on how to use it. He also invented a primitive thermometer and a barometer. He wrote voluminously, notably on the long-debated phenomenon of motion.

When Cosimo II married in 1608, Galileo produced, as a kind of wedding present for his future patron, a 56-ounce lodestone (magnet) capable of lifting over twice its weight in iron. The astronomer proposed the lodestone as a fitting emblem of Cosimo's own strength and powers of attraction.

The following year, two events occurred that would change Galileo's future. First, the old Duke of Tuscany died, leaving the way clear for his son to assume his position.

Second, Galileo heard of a Dutch invention, a "spyglass," which brought far distant objects near. Galileo set to work and, by the end of the year, produced his own version with much greater magnification.

Early in January 1610, Galileo made a number of discoveries, using the spyglass he continued to upgrade. He found mountains on the moon, saw that the Milky Way was actually composed of stars, and discovered four satellites around Jupiter, which he named the "Medician stars." He published these findings in a paper titled "The Starry Messenger," which, of course, he dedicated to the new Grand Duke Cosimo II.

Ousting Aristotle

His discovery and publication brought him the long-dreamed-of appointment as Cosimo's court mathematician. But as Galileo's fame grew, so did powerful opposition to his work, as it began to shake the foundations of a worldview based on Aristotle's assumptions about the cosmos.

The common understanding was that the universe was a set of nested concentric spheres, with our own planet at the center. Our moon was recognized as a satellite undergoing constant change, but the objects in the spheres beyond were immutable—an aspect of their perfection, according to Aristotle.

But Galileo, with his fascination for mathematics, insisted that the same measurements that worked on earth applied also to celestial spheres. He had already proved by verifiable experiment that Aristotle was wrong about falling objects. Now he further embarrassed Aristotelians by intervening in the effort to cast a new bell for Florence's city tower.

The city fathers of Florence, impressed with Galileo's steadily increasing fame, commissioned him to find a way to cast a new bell for the town. None of the local craftsmen could understand why the wooden mold for the bell's inner surface kept rising when molten metal was poured between it and the mold for the outer surface. Taking his cue from the ancient Greek Archimedes, Galileo explained that bodies must be heavier than the volume of liquid they displace or they will float to the surface. This refuted Aristotle, who claimed objects floated when they "pierced" the skin of a liquid and escaped from it. By increasing the pressure on the inner mold, the Florence bell-casters succeeded in their task.

So grateful were the city fathers for Galileo's solution to their problem that they held a state dinner at which the entertainment was a debate between Galileo and visiting clergy on the Aristotelian doctrine regarding liquids.

Among the guests was Cardinal Mafeo Barberini, who was impressed enough with Galileo that when he returned to Rome, he championed the astronomer's revolutionary ideas at the papal court.

Neither Barberini nor Galileo could foresee how their initially friendly relationship would change in the years to come.

War over the heavens

But now Galileo began to have serious detractors. Initially it was not the theologians who balked at Galileo's ideas. Mathematicians at the University of Pisa were so outraged that Galileo dared to challenge Aristotle that they refused to even look through his telescope at the stars.

Aristotle was the authority not just for physics, but for metaphysics as well. In the late thirteenth century, Thomas Aquinas had organized all current knowledge on a system based on the ancient philosopher's newly translated works. This had supplied Western philosophers with a powerful tool for making sense of the world. Whoever dismissed Aristotle's assumptions undermined the foundation of Aquinas's great cathedral of thought.

Even more serious was the charge that Galileo's teachings were inconsistent with those of the Bible. In 1613, the Dominican friar Tommaso Caccini preached a sermon in Florence attacking Galileo's views as heretical because they contradicted passages in Joshua where the sun stands still during the battle of Gibeon.

Galileo wrote to Benedetto Castelli, a former student, explaining his way of reconciling Scripture with scientific discoveries. Both the Bible and nature "proceed alike from the divine Word," he wrote. The Bible was given to reveal by divine revelation what human reason could not, unaided, understand—that is, matters of faith necessary for salvation. In Joshua, the Holy Ghost had shaped his language to take account of common concepts of the universe.

"But," concluded Galileo, "I do not feel obliged to believe that the same God who has endowed us with senses, reason and intellect has intended us to forego their use."

To support his position, Galileo reached back farther than Aquinas, to Augustine, who had himself addressed the question of cosmology, concluding that the shape, location, and motion of heaven as well as the stars were irrelevant to the matter of salvation, his chief concern. Quoting another of the Church Fathers, Galileo added that in the Bible, "the intention of the Holy Ghost is to teach us how one goes to heaven, not how heaven goes."

Somehow this letter fell into the hands of Caccini, who was ill-prepared to debate astronomy and whose grasp of exegesis was not much better. In his sermon denouncing Copernicanism, he used as the clincher Acts 1:11: "Ye men of Galilee, why stand ye gazing up into heaven?" A mangled version of Galileo's letter was sent to the Inquisition in Rome.

Hearing of this, Galileo sent his original version. (He later polished his letter and published it as "Letter to the Grand Duchess Christina," who had been particularly troubled by these questions.) But he was still not much alarmed. He knew he had a powerful friend in Bellarmine at the Vatican. He also knew that many of the best minds in Italy, including the Vatican's mathematicians, were convinced by the proofs of a heliocentric universe Galileo's observations provided. Caccini's Dominican superior was so embarrassed that he sent a letter of apology to Galileo.

But Caccini wasn't done. In 1615 he gave an unsolicited deposition to the Inquisition about Galileo's views, which demonstrated only his own ignorance of the subject. Nevertheless, the committee of theologians to whom the Inquisition referred the matter rendered their judgment, early the next year, that Copernican theory was "absurd in philosophy and formally heretical."

Thus Pope Paul V ordered Cardinal Bellarmine, Galileo's advocate in Rome, to warn the astronomer that henceforth he was not to hold or defend the Copernican theory. The following month, Copernicus's book On the Revolutions was put on the official Index of banned books. Before he left Rome, Galileo had an audience with the Pope, during which Paul V assured him that he had not been on trial in Rome nor had he been condemned—an official declaration Cardinal Bellarmine confirmed in a letter to Galileo the following month.

Nevertheless, the warning got Galileo's attention. He returned to Florence and took up his investigation of more terrestrial problems in physics, like figuring out a way to determine longitudes at sea, and continued his earlier work on moving bodies.

The heavens themselves, however, now seemed to conspire against Galileo's church-imposed silence on celestial subjects. In 1618, three new comets appeared in the sky. Scholars and others, including the Grand Duke of Austria, wrote to Galileo requesting his opinion about the comets.

Meanwhile, a Jesuit mathematician at the Collegio Romano published a paper on the comets, one that Galileo found erroneous. Despite his ban, he could not bring himself to stay out of the fray. He worked with one of his students, composing a rebuttal, which was published under the student's name.

No one was fooled by this ruse. In fact, when the Jesuit mathematician published a reply—under his own pseudonym—he titled it "The Astronomical Balance, on which the Opinions of Galileo Galilei regarding Comets are weighed."

A friend in Rome?

This cat-and-mouse game does not appear to have damaged Galileo's relationship with his ecclesiastical friends in Rome. The following year, 1620, Cardinal Barberini sent him a poem he had composed in honor of Galileo. But as another year began, Pope Paul V died. His death was quickly followed by that of Cosimo II de' Medici, Galileo's patron.

Had the astronomer been a more astute politician, he might have recognized that his position was now more precarious. But Galileo seems rather to have imagined that the ban, if not officially lifted, had at least been forgotten in some dusty corner of the Vatican. He now composed a response to "The Astronomical Balance," titled "The Assayer." When the Roman censors gave their permission for its publication under his own name, Galileo breathed a sigh of relief.

Another death occurred the following month—this one seemingly providential. The deceased was Pope Gregory XV. Now Galileo's longtime friend, Cardinal Barberini, became Pope Urban VIII. The astronomer must have felt he was home free.

Galileo went so far as to change the dedication of "The Assayer" from his late patron to the new pope. Urban showed no sign of displeasure at this honor and indeed, when Galileo was in Rome the following year, granted him six audiences. During these, the new pope assured the astronomer that he was now free to write about the Copernican theory, provided he treated it as theory, not fact.

Returning to Florence full of confidence, Galileo set to work upon the manuscript that was to prove his undoing—Dialogue Concerning the Two Chief World Systems. The years spent in silence about the subject must have sorely chafed his pride, for he cast the work in the form of a satirical dialogue between two rivals, one supporting the Copernican view, the other—made to look a thick-headed fool—arguing for the old Ptolemaic version.

Completing the work took several years, during which various charges were levied against him with the Inquisition, all of which were dismissed.

Final verdict

In this interim, however, Urban VIII's focus shifted from such celestial investigations to a more earthly problem—the Thirty Years War. Political alliances were unstable at best, and he could not afford to be seen as soft on Copernicanism if the papacy were to retain its shrinking power. Thus the Dialogue took two years to work its way through the Roman censors, and it was February of 1632 before it finally went to print.

Then, only a few months after publication, word arrived from Rome that Galileo was to stop distributing the new book immediately while the Inquisition further examined its contents.

In October, he was summoned to Rome to appear before the Inquisition, Urban VIII personally presiding. Galileo was now 67 years old and in bad health, but the pope threatened to drag him to Rome in chains if he did not come voluntarily.

For a month, Galileo, while being held under indefinite imprisonment and threat of torture, negotiated with canon lawyers, trying to come to a mutually satisfactory statement of his position. But Urban, his former friend, remained implacable. In the Church of Santa Maria sopra Minerva (where Caccini had become a Master and Bachelor), Galileo finally recanted his stated belief that the earth moves around the sun.

So debilitated was Galileo by his ordeal that it took months for him to make his way back to his villa on the outskirts of Florence. He was not permitted to leave it for the rest of his life, even to visit the doctor.

The aftermath

In the margins of his copy of the Dialogue, Galileo penned a silent rebuttal to the Inquisition: "Who can doubt that it will lead to the worst disorders when minds created free by God are compelled to submit slavishly to an outside will? When we are told to deny our senses and subject them to the whim of others?"

Galileo chafed under his ecclesiastical constraints. And indeed, except for the Scopes trial, no other single event so thoroughly cemented religion's reputation as the enemy of science. Yet he refused to emigrate or apostatize. Perhaps he was simply too old and sick to care. But he did continue to produce new scientific treatises.

Meanwhile, the rest of the world did not forget Galileo. An international succession of admirers, including the French ambassador, smuggled his work to foreign publishers. The young Milton, on his tour of the continent, visited him in his seclusion. The Dutch States General presented Galileo with a gold chain, a high tribute for the Catholic astronomer from that Reformation stronghold. Galileo declined it, however, a gesture for which Pope Urban VIII commended him.

None of these honors would have given Galileo as much satisfaction as the 1992 papal commission that formally acknowledged the church had erred in its treatment of the great Catholic astronomer.

Virginia Stem Owens is a writer living in Huntsville, Texas, who also serves on the editorial board of Books & Culture.