The most fateful event in the life of Galileo Galileo actually occurred 21 years

before he was born at Pisa in 1564. De Revolutionibus Orbium Coelestium

(On the Revolutions of Celestial Spheres) by the Polish mathematician,

astronomer and cleric Nikolaus Copernicus was published in 1543,

the year of its author's death.

Soon the implications of the book went off like a stick of dynamite in the history of both science and the Church. Copernicus' book contradicted virtually everything the Church believed - and taught - about the Heavens and the way the Earth, the planets and the Sun operated. Galileo, to his great cost, later became a Copernican, convinced that De Revolutionibus stated the truth, while the Church was wrong. This was

Galileo Galilei made astronomical observations that persuaded him of the veracity of the theories of Nikolaus Copernicus. Copernicus's book on planetary movements, De Revolutionibus, revolutionized the science of astronomy.

very dangerous thinking in Galileo's time. In endorsing and then spreading ideas that fundamentally challenged the teachings of the Church, Copernicus and his followers were vulnerable to charges of heresy. The Church and the papacy could be utterly ruthless in their efforts to suppress any opinion on any subject that diverged from the truth as they upheld it. This attitude had noticeably hardened since the middle of the sixteenth century, when the breakaway Protestants confronted the Catholic Church with the most fundamental threat it had ever faced.

This may have been a reason why Copernicus took the precaution of flattering Pope Paul III by dedicating De Revolutionibus to him and also why he held back from having his book published in his lifetime. The decision was prescient. The heliocentric theory escaped religious condemnation for only three years after the death of Copernicus, until 1546, when a Dominican monk, Giovanni Maria Tolosani, denounced his ideas and strongly asserted the unquestionable truth of Scripture. Criticism went little further than that for the moment, but in around 1609, when official action was taken to suppress the work of Copernicus, it was Galileo Galilei who first came into the firing line.


The beliefs championed by the Church derived from the theories of two astronomers of ancient Greece, Aristotle who lived in the fourth century BCE and Ptolemy, who lived in the second century CE. Within the medieval Church, their theories were held to be immutable truths confirmed by Holy Scripture. According to the Aristotelians, as the supporters of Aristotle were known, these truths were, therefore, impossible to change and heresy to challenge. The ancient, geocentric theory held that Earth was sited, motionless, at the centre of the Universe while the Sun revolved round it. One of the 'proofs' for this Earth- centred theory could be found in the Bible, where in Psalm 104, verse 5, it says: 'He set the earth on its foundations; it can never be moved.'

Copernicus' heliocentric (Sun-centred) theory disputed this statement, maintaining that it was the Sun that occupied the centre of the Universe, and was circled by the Earth and the other planets of the Solar System, which were then known as 'wandering stars'. The Sun might appear to move across the sky during the day, but this, Copernicus maintained, was an optical illusion: the appearance of movement came from the motion of the orbiting Earth.

In endorsing and then

spreading ideas that fundamentally

challenged the teachings of the

Churchy Copernicus and his

followers were vulnerable to

charges of heresy.


In Pisa, Galileo was considered an arrogant upstart for consistently seeking to prove that concepts of science approved by the Church were mistaken. He became so unpopular that, in 1592, he left for another university, in Padua, located in the rich and powerful Republic of Venice. This proved to be a beneficial change of scene. The Venetian Republic had a much more tolerant attitude towards dissent than other Italian city-states and vastly more than Rome, where police-style methods were used to stamp it out. In Padua, Galileo mixed with highly ranked, influential Venetians and was able to discuss his ideas with much greater freedom than the situation in Pisa had allowed. In this healthier intellectual atmosphere, Galileo explored the science of ballistics and invented the thermoscope, an early form of the thermometer, and the geometric compass, a type of pocket calculator.

An engraving of Pope Paul III. Copernicus dedicated his book De Revolutionibus to the pontiff as a means of flattering him and hopefully averting criticism from the Church.


Since its earliest days, the Christian Church had had its breakaway groups, dissenters, sects and schisms. But none of them equalled the major shift in faith that occurred during the Reformation, when the Protestant movement broke away from the Catholic Church, renounced the jurisdiction of the Pope and set up its own beliefs and style of Christian worship. This greatest schism of them all is still in evidence today. The fundamental break between the Protestant and Catholic faiths was set off on 31 October 1517 by Martin Luther, a German monk, theologian and university professor. Luther wrote to Albrecht, the archbishop of Mainz and Magdeburg criticizing the activities of Peter Tetzel, a Dominican friar and Pope Leo X's commissioner for indulgences. Tetzel was in Germany to sell indulgences as a means of raising money to rebuild St Peter's Basilica in Rome.

Catholics classed donating money to the Church, through indulgences or any other means, as 'good works', but Luther did not agree. In his Disputation ...on the Power and Efficacy of Indulgences, later known as The 95 Theses, which he attached to his letter, Luther insisted that only God could grant forgiveness for sins and that salvation could not be acquired by buying indulgences. But the dispute over indulgences was only the start. Luther also attacked the Catholic practice of barring Christians from reading the Bible for themselves, and instead insisting that they must have 'ignorant' and 'wicked' priests explain it to them. Instead of the Catholic concept of the pope as the mediator between God and Jesus Christ on behalf of humanity, the Protestants maintained that Jesus was the only mediator. The only means of obtaining eternal salvation, the Protestants asserted, was through faith in Christ, rather than charitable works, as the Catholics believed.

The Reformation and the Catholic response, known as the Counter-Reformation, eventually changed the map of Europe, with the north turning largely Protestant and the south remaining Catholic. In Galileo's time, the dispute between the two churches remained a controversial issue and, as Galileo himself discovered, the much-feared Inquisition and its horrifying methods were put in place to crush any sign of heresy or dissent which might lead to further fracturing.


Then, in 1609 Galileo heard talk of a spyglass, later renamed the telescope, a new invention pioneered by a German optician, Hans Lipperhey. At once, Galileo recognized the telescope as a huge leap forward in optics that could revolutionize the practice of astronomy. He set about constructing his own telescope, which was much more powerful than Lipperhey's original, magnifying objects two or three times over. Subsequently, Galileo built another telescope with 32-times magnification, which he believed could show him the true magnificence of the heavens, and open the way to new discoveries. On an icy night in January 1610, Galileo wrapped himself in a thick cloak, climbed to the highest room of his house in Padua and spent the hours until dawn surveying the sky. He did the same the next night, and the next, until he had recorded a full month of observations. The record was a revelation. Almost everywhere he looked, Galileo found that the Heavens differed fundamentally from the sky according to Aristotle, Ptolemy and the popular notions that stemmed from their theories. The Moon was not smooth, as Aristotle had taught, but rough and pitted with craters. Earth was not the only planet to have a satellite: Galileo observed four moons orbiting the planet Jupiter. He also saw proof that Venus, like Earth, orbited the Sun.


Galileo had argued against the official papal line on astronomy and the sciences ever since he was in his mid-twenties and gave public lectures in mathematics at Bologna in 1588.The following year, he moved on to teach the subject at the University of Pisa. The mathematics Galileo was supposed to impart to his students was, of course, the sort that had been handed down from ancient times. What he taught instead was that the theories of Aristotle and Ptolemy were not always correct. For one thing, Galileo challenged Aristotle's ideas about falling objects. Heavy objects, he said, did not fall faster than lighter ones, as Aristotle maintained. Galileo proved his theory by dropping two different-sized cannon balls from the top of the bell tower at Pisa, commonly known as the Leaning Tower of Pisa. The cannon balls reached the ground at virtually the same time, although one hit the ground measurably later than the other. Despite the small discrepancy, Galileo maintained that Aristotle's ideas had been disproved.

(Interesting….. what  if  you  dropped  a  cannon  ball  and  a  tennis  ball?  If  two  different  sized  cannon  balls  hit  the  ground  at  a  measurable  later  time  from  each  other….. how  would  a  tennis  ball  and  cannon  ball  measure  differently  in  hitting  the  ground?  Keith Hunt)

The scene at the Leaning Tower of Pisa in around 1589 when, according to his secretary, Galileo disproved the theory that heavy objects fall faster than lighter objects.


In 1604, Galileo witnessed a supernova, an exploding star, which led him to challenge Aristotle's view that the state of the heavens as seen from Earth was permanent and unchanging. A supernova, Galileo believed, proved beyond doubt that this idea was false. For a start, it showed that the lifetime of a star was finite.

One way in which a supernova occurs arises after the core of an ageing star ceases to generate energy. After that, it collapses into a neutron star or black hole, heats up to explosion point and blows up, driving its outer layers deep into space. At that juncture, the supernova can illuminate the entire sky with a massive burst of radiation and may remain in view for several weeks or months before fading away. Galileo was fortunate to witness this most spectacular display because supernovae occur only once in a half-century and being in the right place at the right time in order to witness one of them usually requires regular night-time surveillance of the stars. In addition, Galileo observed his supernova without the aid of a telescope, which was not invented until 1609. An intriguing aspect of this event is that the supernova Galileo saw in 1604 must have exploded thousands or even million of years previously: the Universe is so unimaginably vast that the explosion could take all that time to travel through space until it came within sight of Earth. By then, of course, the star itself was long dead and gone.

Galileo drew diagrams of planets, including Earth, in motion around the Sun. This was contrary to church teachings which held that the Sun orbited the Earth.

Galileo spent many hours observing the stars and planets through his telescope.


Galileo wrote a short book, The Messenger of the Stars, about Jupiter and its newly discovered moons. It was an instant bestseller and all 550 copies printed sold out within a week of publication in March of 1610.The book created great excitement, for Galileo had revealed a vast new area of knowledge and understanding. One of Galileo's admirers at this time was Cardinal Maffeo Barberini, a member of a very rich, very powerful family that was influential in Rome and Florence. Barberini first met Galileo in 1611 and appreciated the astronomer's punchy manner and his skill in debate. His admiration was so great that he once wrote to Galileo: 'I pray the Lord God to preserve you, because men of great value like you deserve to live a long time to the benefit of the public.'

However, Barberini was very much a man of the world and was too astute not to know a dissenter when he saw one. He was also wary enough of the direction Galileo's work was taking to make sure that he kept up to date with his research. At some point,

Galileo's book Sidereus Nuncius (The Messenger of the Stars), published in 1610. The book contained his observations of the night sky, made over a full month.

the Cardinal was sure, he would have to warn Galileo away from taking his discoveries too far and so treading on territory where the Inquisition would be waiting for him.

At some point the Cardinal

was sure he would have to warn

Galileo away from taking his

discoveries too far ...

Partly, the Cardinal's caution was sparked by a change of heart in papal circles about the value and veracity of De Revolutionibus. The publication of Copernicus' groundbreaking book had been pioneered by less conservative churchmen who had pressured Pope Paul III to accept the author's dedication to him.

Subsequently Paul III, who served as pope between 1534 and 49, and another pontiff, Gregory XIII, who was elected in 1572, gave their approval to some of the doctrines, which De Revolutionibus contained.

But Paul was not really happy about sanctioning Copernicus' ideas. In 1542 he revived the Inquisition for a reason that had nothing to do with the Polish astronomer and his theories: it was aimed at suppressing the Protestants who were fracturing the Church with their own revolutionary concept of Christianity. But as time was to prove, Paul's new Roman Inquisition would serve for any other charge of heresy that popes, present or future, might care to bring.

The Inquisition was used for precisely this purpose after 1614, when a priest called Father Tommaso Caccini denounced Galileo and his 'heretical' opinions concerning the motion of the Earth, as set out in The Messenger of the Stars. The import of Galileo's book

Galileo demonstrates his telescope to Venetian nobles in 1610. This telescope was able to magnify 32 times and was more powerful than any that preceded it.

and the observations it recorded were clear for all to see: it inferred that the Church had been peddling inaccuracies and, far from revealing God's truth to the people, they had been concealing it.

By this time, Galileo had gathered a degree of support for his Copernican ideas in the universities, among the intelligentsia and even in the Church. This popularity, combined with the perils of Protestantism, made Galileo's teachings appear all the more dangerous.

Galileo's book inferred that the

Church had been peddling

inaccuracies and far from revealing

God's truth to the people they had

been concealing it.

Galileo's position was not helped by the publication of a pamphlet written by one of his acquaintances, the Carmelite cleric Paolo Antonio Foscarini, in which he defended Copernicus and his heliocentric theory. Foscarini tried to have it both ways, stating that it was possible to justify Copernicus with quotations from the Bible. Cardinal Robert Bellarmine, a Jesuit and one of the few to hold the title Doctor of the Church, soon saw through Foscarini's device and wrote to him in very stern terms:

To want to affirm that in reality the Sun is at the centre of the world and only turns on itself without moving from east to west, and the Earth...revolves with great speed about the a very dangerous thing, likely not only to irritate all scholastic philosophers and theologians, but also to harm the Holy Faith by rendering Holy Scripture false.

Foscarini's book was considered so seditious and heretical it was soon placed on the Index of Prohibited Books. The Foscarini affair, widely viewed as a scandal in papal circles, prompted virulent anti-Copernican feeling still simmering by the time Galileo arrived in Rome. In this atmosphere, there was little chance Galileo could obtain an unbiased hearing for his own views. Even so, he did get a warning from his friend Cardinal Barberini. Barberini did not confront Galileo personally but instead sent a secretary, Giovanni Ciampoli, who idolized the astronomer, to tell him:

Signor Cardinal Barberini who, as you know from experience, has always admired your qualities, said to me yesterday evening that he would appreciate greater caution in this issue, to avoid going beyond the reasoning of Ptolemy or Copernicus or finally that you should not pass beyond the limits of physics or mathematics, because the theologians claim that interpreting Scripture is their prerogative.

Cardinal Roberto Bellarmine, an eminent theologian, treated Galileo far less tactfully. Bellarmine was a Jesuit, a member of an organization that made loyalty to the teachings of the Catholic Church its first rule of obedience. Bellarmine, therefore, had never deviated from the Church's view that the positions and functions of the Sun and the Earth were as the Bible stated. According to the Cardinal, all scholars who studied the Scriptures 'agreed in interpreting them literally as teaching that the Sun is in the Heavens and revolves around the Earth with immense speed and the Earth is very distant from the Heavens at the centre of the universe, and motionless. Consider, then,' Bellarmine continued, 'whether the Church can tolerate that the Scriptures should be interpreted in a manner contrary to that of the Holy Fathers and of all... commentators, both Latin and Greek.'

Galileo was never going to get past a cast-iron attitude like this, any more than he could dissuade those priests who looked through his telescope at the Moon and concluded that since the instrument was artificial, then the heavily cratered surface they saw through it must be artificial, too.

There is an engraving of Cardinal Bellarmine, who warned Galileo that he must not support or defend the 'heretical' theories of Copernicus,


Galileo wrote numerous letters to high-ranking churchmen, and also to his own students in which he justified his Copernican-influenced theories. In one of his letters., originally written in 1613, but later expanded into the Letter to the Grand Duchess Christina of Tuscany, he pointed out the vast difference between the faith-led mentality and the scientific approach. Galileo wrote:

Some years ago I discovered in the heavens many things that had not been seen before our own age. The novelty of these things... stirred up against me no small number of professors… Showing a greater fondness for their own opinions than for truth, they sought to deny and disprove the new things, which, if they had cared to look for themselves, their own senses would have demonstrated to them. To this end, they hurled various charges and published numerous writings filled with vain arguments.... Men who were well grounded in astronomical and physical science were persuaded as soon as they received my first message. Well the passage of time has revealed to everyone the truths that I previously set forth...

This was a case of irresistible force meeting immovable object, for, as the wording of his letter shows, Galileo was arrogantly confident that he was in the right while his opponents, the so-called Aristotelians, were equally certain that the truth was on their side. But Galileo should not have been so sure that 'everyone' agreed with him. In 1616, when he made a special journey to Rome to defend himself against Caccini's allegations, he encountered the full might of the Church and the papacy as they set their faces implacably against him.

The Grand Duchess Christina of Tuscany, born in 1565, was a grand-daughter of Catherine de' Medici. Galileo wrote his Letter to Christina on the relationship between religious revelation and science in 1615.



It was not surprising then, that Bellarmine went much further than Barberini's kindly meant, softly worded admonition and told Galileo bluntly that an edict had been promulgated in February of 1616 utterly condemning the heliocentric doctrine as heretical. A month later, on 5 March 1616, De Revolutionibus was listed on the Index of banned books. From then on, anyone who sought to promote or even discuss Copernicus' theory of the stationary Sun and the moving Earth was a heretic and, Bellarmine added, the Inquisition knew very well how to deal with them.

Bellarmine's warning thoroughly alarmed Galileo, which was precisely the Cardinal's intention. Galileo was well aware of the punishments for heresy -interrogation, torture and incarceration and, for those found guilty, death by burning at the stake. There was, for instance, the precedent of a Dominican friar, Giordano Bruno, who was burned to death in 1600 for suggesting, like Copernicus and Galileo, that the Earth moved around the Sun. Bruno compounded his 'heresy' by suggesting that there were other worlds in the Universe like Earth, with their satellites and Sun. With such an example of the extreme dangers of heresy staring him in the face, Galileo seems to have thought twice about promoting Copernicus' theories as blatantly as he had done before. Galileo was, in any case, now 52 years old, which was considered quite elderly in the seventeenth century, and his health had been poor for some time. It seemed prudent, therefore, to lie low for a while.

A Dominican friar Giordano

Bruno; was burned to death in 1600

for suggesting that the Earth

moved around the Sun.


After he returned from Rome, Galileo lived at Arceti, his house near Florence and appeared to have been tamed by his unpleasant encounter with Bellarmine and the threats of the Inquisition. He studied three comets that appeared, flashing through the sky over Florence, in the autumn and early winter of 1616 and wrote a book about his findings entitled The Assayer, which was published in 1623. For the rest, Galileo assumed the leisurely life of a country gentleman, taking rides through the countryside on his mule, or hawking with his falcon on his wrist. At other times, he tended the vines he grew in his garden. But this backwater existence provided precious little stimulation for Galileo's lively mind. The situation could not go on for much longer. In 1623, Cardinal Barberini had been elected pope as Urban VIII. This seemed to be a piece of good fortune for Galileo because, despite the showdown in Rome in 1616, he had remained close friends with Barberini and the two had exchanged an ongoing correspondence ever since. As a compliment to the new pope, Galileo dedicated his book The Assayer to him. Urban was so impressed with it that he ordered extracts from the book read at public meetings. He also invited Galileo to visit him in Rome but ill health prevented the astronomer from taking up the invitation until the spring of 1624.

Pope Urban came to meet Galileo when he arrived and the friends soon made up for lost time with 

                           Galileo assumed the leisurely life of

a country gentleman taking rides ...

hawking with his falcon on his wrist.

At other times he tended the vines

he grew in his garden.

regular meetings - six over the next five weeks. Together they strolled through the Vatican gardens spending many hours talking and exchanging ideas, including Copernicus' heliocentric theory. Galileo left Rome at the end of his visit on 8 June 1624, taking with him a letter to the Grand Duke Ferdinando II in which Pope Urban eulogized his friend as 'a great man whose fame shines in the Heavens and goes on Earth far and wide'. Praise indeed, and it encouraged Galileo to believe that the debate about the heliocentric theory, so savagely closed down in 1616, could be safety reopened.

There is a statue of the Dominican monk Giordano Bruno was erected in the Campo de Fiori, Rome where he burned at the stake in 1600 for supporting Copernicus' theory and other heretical ideas.


Fact dressed up as fiction or, in the case of Galileo's Dialogo, as imaginary discussion, had already been used in 1611 by Johannes Kepler, the German mathematician and astronomer who was a contemporary of Galileo and another adherent of Copernicus' heliocentric theory. Kepler's Somnia, (The Dream) made a treatise on interplanetary travel read as if it were a fantasy about a journey to the Moon, and has since been called the first work of science fiction. There was, of course, no guarantee that the Inquisition would fall for the trick the likes of Galileo or Kepler was playing on them, and Somnia led to alarming consequences for Kepler's mother Katherina. In 1617, she was accused of witchcraft on the basis of her son's book. Fortunately, the old lady was acquitted and released in 1621, mainly due to Kepler's vigorous arguments in her defence. Nevertheless, the danger involved was all too evident and Galileo wanted to take no chances. He decided to deliver the finished manuscript of his Dialogo to Rome in person and see it through the approval and printing processes. He was asked to make small changes - nothing too drastic - and the book was finally published in February of 1632. It was an instant success and sold out a very short time after it went on display in the bookshops.  

Johannes Kepler, born in Germany in 1571, was an astronomer, astrologer and mathematician. A key figure in the 17th-century revolution in astronomy, he was best known for his laws of planetary motion.

The universe according to the Ancient Greek astronomer and  mathematician Ptolemy, showing Earth at the centre with the Sun orbiting around it.


Galileo now planned to write another book, Dialogo Dei Massimo Sistemi (Dialogue Concerning the Two Chief World Systems), this time in the form of a three-way conversation, with two characters discussing the theories of Copernicus and the third putting forward the views of Ptolemy. By using fictional characters reciting lines as in a stage play, Galileo imagined he might get round objections from the Inquisition and the Sacred Congregation of the Index. (The Sacred Congregation was the body within the Catholic Church that decided on which books were 'heretical' and should therefore not be read by Catholics.)

This painting by Joseph-Nicolas Robert-FIeury (1797-1890) portrays the 68-year-old Galileo Galilei on trial for heresy in Rome in 1633.

Even so, his experience in Rome in 1616 had made him wary of upsetting the papal authorities. They had it in their power to destroy any idea with which they did not concur, and do the same to whoever put forward or supported that idea. Galileo took the precaution of testing the content of the Dialogo on the Jesuit jurist Francesco Ingoli, who had once criticized his Copernican views. Galileo wrote to Ingoli, putting the arguments in favour of Copernicus' and the heliocentric theory, but he was careful to add: 'I do not undertake this task with the aim of supporting as true a proposition that has already been declared suspect and repugnant.' Instead, Galileo continued, he wanted to set out all the arguments for and against Copernicus so that all might be fairly judged.

Ingoli received Galileo's letter in Rome in December 1624. Galileo waited anxiously for a

Using fictional characters reciting

lines as in a stage play Galileo

imagined he might get round

                                objections from the Inquisition...

furious reaction from Pope Urban, but there were no fireworks, no irate demands that the astronomer return to Rome immediately and explain himself and no rumblings from the Inquisition. Believing the coast was clear Galileo went ahead with the Dialogo. It proved to be a monumental work, running to some 500 pages and taking six years to complete. It was a painful process, too. Galileo was 66 years old by the time the task was finished and suffered badly from arthritis, which made writing difficult for him.

      Pope Urban could never play the game in which authors used verbal

trickery to avoid censure by the

religious authorities while still

disseminating their heretical ideas.

In producing his Dialogo, Galileo resorted to a device often used by scientists in Catholic Europe, which was to disguise controversial information by presenting their theories as nothing but intellectual exercises or giving them the appearance of fiction.

Galileo was understandably pleased with himself when Dialogo was approved, but there was one important thing he had overlooked. He failed to realize that Pope Urban could never play the game in which authors used verbal trickery to avoid censure by the religious authorities while still disseminating their heretical ideas. In this, Galileo may have mistaken the

In supporting the theories of

Ptolemy like all popes before him

Urban was peddling the

brainstorms of a fool.

latitude Urban had allowed him as a cardinal: friend or no friend, this was not possible for Urban as pope. It had grown even more impossible because in 1625 news reached Rome that the German Protestants, the great enemies of the Catholic Church, had accepted the heliocentric theory.

The pope's new hard-line attitude became all too clear to Galileo after he presented Urban with a copy of the Dialogo. Urban was incandescent with rage when he saw what Galileo had done with Simplicius, the character who voiced the opinions representing Ptolemy. Whereas the other two voices, Salviati, a scientist and Sagredo, an intellectual, made sense when they spoke for Copernicus and his theories, Simplicius, as the name suggested, expressed himself like an idiot and a buffoon. As one of Galileo's admiring friends, Tomasso Campanella put it:

Simplicius seems to be the plaything of this philosophical comedy;, which at one and the same time, shows up the foolishness of his sect, the empty words, the instability and obstinacy and whatever else you like to mention.

Not only was Simplicius ridiculed throughout the book, Galileo managed to get in a sly dig at the Aristotelians, writing that they were 'content to adore shadows, philosophizing not with due circumspection but merely from having memorized a few ill-understood principles'. Even worse was the notion, put about by infuriated Aristotelians, that Simplicius was a caricature of Pope Urban himself.


Whether or not that was Galileo's intention, Urban, it seems, believed it was. Galileo's message was obvious. In supporting the theories of Ptolemy, like all popes before him. Urban was peddling the brainstorms of a fool. No wonder Urban was so incensed and sadly, his friendship with Galileo died there and then. Understandably, Urban felt betrayed and just as he could be an effusive friend, he could also be an implacable enemy. As Francesco Niccolini, the Tuscan ambassador in Rome, wrote of Pope Urban:

When his Holiness gets something into his head, that is the end of the matter, especially if one is opposing, threatening or defying him, since then he hardens and shows no respect to anyone.... This investigation is really going to be a troublesome affair.

Niccolini was right. Towards the end of 1632, Galileo was summoned to Rome where he was ordered to appear before the Inquisition. Galileo tried desperately to postpone the evil hour, pleading ill health and the outbreak of plague in Florence, which would make it dangerous for him to move. But Urban was adamant. The astronomer, now 68 years old, was medically

Painting: A suspected heretic being tortured by the Inquisition in the 17th century. The Virgin Mary and the baby Jesus 'watch' the scene from an adjacent wall.

examined and judged fit to travel. Urban decreed that unless he was found to be gravely ill, virtually dying in fact, he should be arrested and forcibly brought to Rome. Rather than suffer such humiliation at the hands of his former friend, Galileo left Florence of his own volition on 20 January 1633. He spent a short time in quarantine at Acquapendente 198km (123 miles) from Florence, and after being cleared, arrived in Rome three weeks later, on 13 February. There, he stayed at the Villa Medici as a guest of Francesco Niccolini, a concession he was allowed, despite Urban's enmity, because of his age and his parlous state of health.

This page from a 1653 edition of The Messenger of the Stars shows Galileo's sketches of the cratered surface of the moon. His discovery of earth-like mountains and valleys on the moon challenged the view that the heavens were perfect and unchanging.

Galileo was obliged to wait two months before he was finally interrogated. The reason for the delay was that the Inquisition could not make up its mind how his case should be handled. Urban had always been sure that there could be no scientific or theological proof for the heliocentric theory, but others at the Holy Office were not so certain, and feared that if such proof were actually forthcoming, it might result in the revelation that God, the Bible, the pope and the Catholic Church had made a fundamental mistake. That would be embarrassing to say the least but, at worst, it could have detrimental consequences for the credibility of the Holy See.

As if this were not enough, there was also the problem of how to prosecute a man as famous and admired as Galileo, who was also the author of a book, the Dialogo, approved by the Friar Master of the Sacred Palace, the papal court at the Vatican. Pope Urban, it seemed, knew nothing about it and denied ordering a licence to be granted for the publication. Yet, the book had been published and scored a great success. Much as he wanted to come down hard on his one-time friend and bring the Dialogo into court as prosecution evidence, even Pope Urban could see that using the book to discredit Galileo was not an option.

After weeks of agonizing over these problems, the Holy Office of the Inquisition at last decided to proceed with the trial. Galileo was interrogated on

the Holy Office ... feared that if such

proof were actually forthcomings

it might result in the revelation that

God; the Bible the pope and the

Catholic Church had made a

fundamental mistake.

12 April 1633. Under questioning, he stoutly maintained that he not deviated from the ban on De Revolutionibus or the opinion against Copernicus' heliocentric theory as set out in the Edict of 1616. Furthermore, he had presented the Copernican theory as a hypothesis only and denied that he had ever said it was true.


Galileo's dogged line of defence put the Holy Office in a quandary. If the Inquisition were to save face, as they must, it could not simply let Galileo go unpunished. One possible alternative was simply to ban the Dialogo and place it on the list of prohibited books, like Copernicus' De Revolutionibus, but that, of course, would amount to letting Galileo off the hook. Pope Urban came out firmly against the idea that the book should be condemned, but not its author. Nothing would do but to prosecute and reach the guilty verdict Galileo's former friend clearly desired.

Normally, at this stage, suspected heretics were handed over to the Inquisition to be tortured until they confessed. The inquisitors gave the accused a last chance to recant by showing them the instruments of torture, which were often blessed by priests before they were used, regarded as they were by the Church as holy tools by which God enabled the Inquisition to return deviants to the one 'true' faith.

It was highly likely that Galileo knew about these instruments and the agony they could inflict. It was not normal practice for the Inquisition to torture the elderly though it remains unknown just how far Galileo, nearly 70 years old in 1633, believed that he would be excused torture on account of his age. However, for a frail and frightened old man, worn down by ill health and anxiety, the mere threat of torture could have sufficed in order to achieve the only other alternative open to the Inquisition: pressurizing Galileo to wear him down until at last he gave in out of sheer fright and exhaustion.

                               The instruments of torture...

were often blessed by priests

before they were used.

[They were] regarded by

the Church as holy tools.

Nearly three weeks after his first appearance before the Inquisition, Galileo returned to the court on 30 April and admitted that in writing the Dialogo, his judgement had been bad. He said:

I freely confess that in several places, it seemed to me that I set forth in such a form that a reader ignorant of my real purpose might have reason to suppose that the arguments on the false side, and which it was my intention to confute, were so expressed as to be calcidated rather to compel conviction by their cogency than to be easy of solution.


Galileo went further and humiliated himself by confessing to 'vainglorious ambition'. After being forced to make this craven statement, Galileo was taken down to the dungeons of the Holy Office where he spent three weeks before appearing again in front of the Inquisition. He was there formally to renounce Copernicus and his theory and present the inquisitors with a written admission of his wrongdoing. He now realized, he said, that the Dialogo had 'accidentally' supported the Copernican view of the heavens whereas the Church had correctly ruled that this view was wrong. Afterwards, on the orders of Pope Urban, Galileo's renunciation was disseminated throughout Catholic Europe, where it was read out in all churches so that all Catholics would know that the great Galileo Galilei had been broken by the will of the Inquisition.

His humiliating submission and the pope's vindictiveness hurt Galileo deeply. He was furious and bitter at his treatment by the Inquisition and his erstwhile friend, who had forced him to make a truly painful sacrifice. He had, after all, been forced to deny the work and the beliefs of a lifetime for the sake of a mistaken theory he knew in his heart was totally wrong. Galileo was still defiant, despite his abject recantation. Niccoloni, together with Galileo's other friends, had to work hard to persuade him to be amenable, even acquiescent, for if he persisted Pope Urban and the Inquisition could unleash upon him their armoury of punishments. If that happened, it was unlikely that the old astronomer could escape a second time. It took Niccolini some time to get through to him. He wrote:

He claimed, nevertheless, that he could defend his opinions very well, but I exhorted him, with the aim of getting things over quickly, not to struggle to uphold them, but to submit to whatever the (Inquisition) might desire him to believe.... He was greatly afflicted by this, and for myself, I have seen what he has landed in as a result of this, and I have great doubts about the safety of his life.


On 22 June 1633, Galileo returned for the last time to the Inquisition, this time to hear his fate. He was dressed for the occasion in long white robes and the conical hat of a repentant sinner and knelt before his judges to hear his sentence. The Inquisition pronounced Galileo guilty of 'heinous crimes' and ruled that he was 'vehemently suspected of heresy'. Galileo replied, 'I curse and detest (my) errors and heresies.'

Galileo had, after all, been forced

to deny the work and the beliefs of a

lifetime for the sake of a mistaken

theory he knew in his heart

was totally wrong.

His book, Dialogo was banned and remained on the Index of Prohibited Books for nearly 200 years. Galileo himself was sentenced to lifelong imprisonment. Afterwards, he was taken down to the dungeons beneath the Holy Office once again and might have stayed there but for the intervention of the young Cardinal Francesco Barberini, the nephew of Pope Urban VIII. Barberini was a great admirer of Galileo, and he managed to persuade his uncle to allow the astronomer to return to the Tuscan Embassy. Ambassador Niccolini was alarmed at the state Galileo was in. 'It is a fearful thing,' he wrote, 'to have to do with the Inquisition. The poor man has come back more dead than alive.'

Galileo ... remained under house arrest, a prisoner of the Inquisition,   forbidden ... to return to teaching.

John Milton, the English author and poet best known for Paradise Lost, visited a rather unwell Galileo in 1638, while the astronomer was under house arrest at Arceti, near Florence.

Niccolini agitated for Galileo to be allowed to go home to Florence. Pope Urban refused but did permit the disgraced astronomer to move to the home of Ascanio Piccolomini, Archbishop of Siena, where he suffered a nervous breakdown. Galileo remained with Piccolomini in order to recover for the next five months. It was not until the end of 1633 that Galileo was allowed to return home to Arceti. Even there, though, he remained under house arrest, a prisoner of the Inquisition, forbidden to receive fellow scholars or scientists as visitors or to return to teaching.



Although Limbo is not an official feature of the Roman Catholic religion, it is connected to it. The word is taken from the Latin limbus meaning edge and describes a condition experienced in the after life by people who die in original sin, but have not been assigned to Gehenna, the Hell of the damned. Purgatory is frequently taken to describe a place of fearful suffering where the souls of sinners atone for their wrongdoings and undergo terrible punishments. In fact, the Catholic Church views purgatory in a much more optimistic light, as a situation where souls of those who die in a state of grace are purified and give temporary punishment, where appropriate. This process prepares them to go to Heaven. Buying an indulgence during life could lessen the length of time a sinner had to spend in limbo or purgatory before their soul was allowed to go on to heaven in the afterlife.

But he could still write and at Arceti he worked on a new book he had started while staying with Piccolomini entitled Two New Sciences., about the sciences of mechanics and motion. However, his disgrace at the hands of the Inquisition made Italian publishers afraid to print it. The Inquisition stood in Galileo's way in Venice and Jesuits ruined his chances of publication in Germany. Eventually, Galileo's friends resorted to smuggling the manuscript over the Alps into the Protestant Netherlands, where papal writ did not extend. The book finally appeared in June of 1638. By this time, Galileo had so ruined his eyes gazing at the stars through his telescopes he had become blind. He was never able to read the printed copy of his last book.

Galileo had so ruined his eyes

gazing at the stars through his

telescopes he had become blind.


Towards the end of 1641, the fever that had afflicted Galileo every winter returned once more, but this time there was no recovery. Galileo died on 8 January 1642 a few weeks before his seventy-eighth birthday. Even in death, Pope Urban remained vengeful. He refused to allow his one-time friend to be accorded a public funeral and sat firmly on the pleas of the great astronomer's friend, the mathematician Vincenzio Viviani that Galileo deserved a monument. Urban's reasons were that through his sins against God and the Catholic Church, Galileo had given rise to 'the greatest scandal in Christendom'. Instead, Galileo was hidden away in a modest grave in the cellar of the church of Santa Croce in Florence.

Almost a century later, in 1737, Pope Clement XII ordered a proper tomb and monument built for Galileo in Santa Croce. But another 350 years were to pass before Pope John Paul II in 1992 reversed the judgments of 1616 and 1633 and confirmed that Galileo had been right.

Galileo's tomb and monument were constructed in 1737 at the Santa Croce church in Florence by Pope Clement XII. By this time, more than a century had passed since Galileo's death.











Keith Hunt