Prior to his famous trial in 1633, Galileo Galilei had been to the city on the Tiber four times. First time in 1611. A year earlier he was called to the court in Florence by the Grand Duke of Tuscany, Cosimo II de Medici, who was also his former pupil, where he received a title of the court philosopher and mathematician, as well as a title of Professor of Mathematics at the University of Pisa, his home town. At the Florentine court he was guaranteed the best conditions to conduct scientific research. When he came to Rome, he was then a figure of some renown and outstanding backing, meaning the protectorate of the Florentine duke. He was invited by the best circles in the city, where with fervor he talked about craters on the Moon which he had just discovered, demonstrating to the amazed listeners, its furrowed surface, while in the papal gardens on Quirinal Hill he garnered respect, showing spots on the Sun. Jesuits received him with respect at the Collegio Romano, where the erudite talked about the planet Venus, which revolved around the Sun, which was in line with the earlier discovery of Copernicus, proving, that the Earth revolves around the Sun as well (and not the opposite), which at that time Church treated as a kind of a hypothesis. And here it must be underlined that the theory  laid out in the work published almost fifty years earlier by Nicolas Copernicus, De revolutionibus orbium coelestium (On the Revolutions of Heavenly Spheres), assuming a heliocentric vision of the universe – in accordance with the preface directed by the author to Pope Paul III – was only a mathematical model. During the times of Galileo, this cautiously expressed thesis gathered more and more support from scientists (although not all), who in the Copernican system saw a scientific truth, based on research and observations, but they did not express this out loud. Galileo was among them. The Jesuits, even before he left Rome, divided into two camps. The first, although skeptical, with interest listened to the words of the scientist from Florence, the second fully renounced them. The Cardinal Inquisitor, Cardinal Robert Bellarmin, belonged to this second group, and already then he directed his attention to the resolute resident of the Florentine court. He, in the meantime had made several significant acquaintances in Rome. He met with the astronomer Christopher Clavius he carefully observed his scientific research, while the members of a private Roman university, Accademia dei Lincei, invited him to join their ranks, supporting and encouraging him to work further. Leaving Rome after a several-month-long stay, Galileo had to leave an unforgettable impression and not just on the Roman intellectual elites. When he met Pope Paul V, the pontiff, reportedly (literally) lifted him from his knees, unequivocally forbidding him, from talking to the pope while kneeling, which was the habit among the less important papal guests. A certain interesting fact provides testimony that even the head of the Church was affected by Galileo’s theories. As soon as he left the city, the Florentine painter and a friend of Galileo, Ludovico Cardi (known as Cigoli), painted a fresco representing the Madonna of Immaculate Conception, standing not – as was the habit in this type of images – on the crescent moon, but on a filled with craters sphere, with a shining glow of the sun in the background. We might say, well, so what, such things happen and are of no great significance, however, this unusual work was created at the top of the apse of the pope’s family chapel (Cappella Paolina) in the Basilica of Santa Maria Maggiore, in which Paul V ultimately wanted to be buried.

A few years later, a book by a clergyman Paolo Antonio Foscarini appeared, in which the author claimed that the heliocentric vision of the world does not have to come in conflict with the teachings of the Church. Two private letters written at that time by Galileo also expressed similar views. The Inquisition began an investigation of Foscarini, while his work along with those of other scientists (e.g. Johannes Kepler) found itself on the index of prohibited books (Index librorum prohibitorum). Galileo, on the other hand, received a letter from cardinal Bellarmin, reminding him that the theory of Copernicus is just a hypothesis. Busy, with his research on the moons of Jupiter and the telescope he did not take a stance on this topic. When he once again visited Rome in 1616, Bellarmin once again presented him with the official version of the Church, according to which God through the Bible, supported the Ptolemaic system, in which the Earth stands still and the Sun revolves around it and the cardinal insisted that Galileo should not in any way disseminate, support or defend the heliocentric system. It must be added that in this same year of 1616, the work of Copernicus also found itself on the index of prohibited books. A few years passed and in 1623 thanks to the encouragement and help of the Roman Accademia dei Lincei, Galileo published his treatise Il Saggiatore (The Assayer), which he dedicated to one of the members of said academy – the poet Virginio Cesarini, but in truth it was destined to the new, open to the world, the arts and science Pope Urban VIII, to whom Cesarini was a trusted advisor. It also was impossible not to notice the papal coat of arms placed on the title page (the three bees of the Barberinis) and thus not recognize the protection of the pontifex maximus for the theories contained within its pages. It was a kind of a pamphlet against the Jesuit priest, Orazio Grassi, who had in one of his earlier publications attacked Galileo. The Florentine academician did not speak directly on the theory of Copernicus, but rather on the subject of natural sciences, which should be based purely on mathematical calculations and observations. Galileo proved, that the task of science is research – by a method of deduction – the order and concomitance of phenomena. During another stay in Rome, the famous scientist, at a clear invitation of Urban VIII, stayed in the salons of his nepots, while the pope himself granted him an audience a full six times, amazed at the ridiculing style of Il Saggiatore and seemed to be encouraging the astronomer to continue his work, also on (the hypothetical) Copernican theory, which he himself did not support.

However, Galileo sure of the pope’s support and his well-grounded scientific position, as well as the protectorate of the Florentine court, but also tired of the constant attacks against him, decided to openly defend Copernicus. After a few years of preparation he decided to publish a book entitled Il Dialogo (Dialogue Concerning the Two Chief World Systems, Ptolemaic and Copernican), which became the source of his long-lasting problems. In 1630 he went to Rome, to receive initial permission to print his work, which would have the form – as the title itself announced – of a dialogue. Since the papal censor, who had favored him until then, stalled with his decision, the impatient Galileo decided to publish his work in Florence and dedicate it, not – as he had originally intended – to the pope but to the Grand Duke of Tuscany – Ferdinand II. In 1632, the book was published, with an illustration which really had explained everything. It depicts three men having a dispute – Ptolemy (the ancient author of the geocentric theory), Aristotle, and Copernicus, but it is the last one – holding a flat model of the Sun in his and, around which the Earth rotates and revolves –   who seems to be the tallest, youngest and the most dominant, while his visage is reminiscent of the face of Galileo. The titular dialogue is conducted between the supporter of Aristotle in the figure of Simplicius and a supporter of the theory of Copernicus.

Galileo enjoyed the publication of his work for nearly half a year, after which the sale of his work was halted by the pope. Why? Historians see in Urban VIII’s actions reasons of doctrinal nature but not only. Of course, it could not have gone unnoticed, that Galileo unequivocally supported Copernicus’s heliocentric theory, thus discarding the thesis of the Church, maintaining that it is simply a mathematical speculation. However, the pope could have also felt offended, since Galileo did not wait for the decision of the Roman censor, meaning he ignored his office and authority. The author with an inborn tendency for satire and ridicule, presented the arguments of Simplicius (whose name could have easily been associated with the word simpliciotto – simpleton), as those   also presented by the pope, ridiculing him in this way. Another reason for the pope’s anger, could have been the dolphins visible on the title page, which could have been seen as mockery of the numerous papal dolphins (meaning nepots) – Francesco Barberini, Antonio Barberini and others, who at that time were more and more criticized, similarly to the pope himself, who was accused of neglecting the spread of Protestantism, and even supporting heretics. In this situation Urban VIII was faced with a difficult task. He did call Galileo to Rome, but the scientist claiming illness and then the rampaging plague and quarantine had the pope wait for him the whole winter. This audacity was noticed, not only at the pope’s court. Galileo was called to the city on the Tiber, but this time by the Roman Inquisition, which in 1633 accused him of spreading heretical views. And while the terrified Galileo, after his second interrogation denied being a supporter of the Copernican theory and assured that his own book seems like something completely alien to him, as if it had been written by somebody else, ten of the judges found him to be guilty. The sentence was not signed by three cardinals,, including the nephew and the most important papal nepot – Francesco Barberini, who spoke in favor of the scientist and influenced the alleviation of the punishment imposed upon him. Ultimately Galileo was sentenced to house arrest in a villa near Florence, while his Dialogue found itself on the index of prohibited books, next to the work of Copernicus.

In exile, with his vision gradually deteriorating, he worked and published until his death.

When news of a planned in Florence funerary monument for the outstanding scientist reached Urban VIII, he stated that erecting an official statue for a heretic is unthinkable. Galileo was buried anonymously. It was not until nearly one hundred years later, in 1737, in the Church of Santa Croce in Florence, that a monumental tomb was created, in the form reminiscent to that found in Rome, commemorating Pope Urban VIII – protector of science, who despite good intentions, did not meet the challenge of the Copernican theory. But he was not the only one.

Only after another three hundred years in 1979, the papal Academy of Sciences at the commission of John Paul II, occupied itself with the case of Galileo. In 1992 the seventeenth-century scientist, who claimed, that the Biblical vision of the world is not opposed to natural sciences, but merely describes the movement of celestial bodies, while it is the former which shows the path to salvation, was rehabilitated.