Galileo was convicted of heresy on this day in history - 22nd June. Image shows an etching of him with a telescope

On this day in history: Galileo Galilei convicted of heresy

History of Italy News

On 22nd June 1633, Galileo Galilei – astronomer, mathematician, philosopher and engineer – often described as ‘the father of science’, was convicted of heresy. It was his second trial, having already been warned about his heretical thoughts in 1616.

The crime of Galileo Galilei was to support the view, with scientific proof,that the sun rather than the earth was the centre of the solar system. Known as the Copernican theory, it was considered heretical by the church.  

Orthodox Roman Catholic beliefs were that the sun moved around the earth: a fact of scripture that could not be disputed.

Galileo had the patronage of powerful Italian families such as the Medicis and the Barberinis following the discoveries he made with his astronomical telescope. The church, however,m had had him under surveillance since 1609, when he published details of observations he had made that supported Copernicus’s theory of heliocentrism.

In 1616 the Copernican view was formally declared heretical and the biblical interpretation of creation was reaffirmed. The section of the Bible which the Inquisition focused on was that which read, “God fixed the Earth upon its foundation, not to be moved forever.”

However, Galileo had permission by Pope Urban VIII, a member of the Barberini family, to continue his studies into Copernican theory. There was a but; he was not to draw definitive conclusions, and he must acknowledge divine omnipotence.

Galileo’s Second Trial

However, in 1632 Galileo published his Dialogue Concerning the Two Chief World Systems – comparing the theories proposed by Copernicus, and the traditional view of the second century astronomer Ptolemy. Galileo favoured Copernicus.

Image of frontispiece from Galileo's Dialogue, which saw him accused, tried and convicted for heresy.

This was a step too far, and the Pope had to act.

Galileo was summoned to Rome for trial by Inquisition in 1633. Despite the strength of his evidence, the judges declared him guilty of heresy. Galileo was made to recant his own findings as “abjured, cursed and detested”.

Galileo had two choices, recant or burn at the stake. Unsurprisingly, he chose the former. He is said to have muttered the words “E pur, si muove” – “And yet, it moves” – after declaring the earth to be a fixed object.

He was sentenced to be imprisoned indefinitely, his Dialogue was banned and the future publication of any of his research was forbidden.  However, the following day the sentence was commuted to house arrest.

Galileo lived out the remainder of his days at his villa at Arcetri, near Florence.  Despite going blind in 1638, he will still able to reconstruct and summarise the discoveries he had made in Two New Sciences. His findings were smuggled out of Italy and published in Holland.

Galileo died in 1642.

Church moves towards vindicating Galileo

In 1758, the Catholic Church dropped the general prohibition of books advocating heliocentrism from the Index of Forbidden Books.

Pope John Paul II, in 1979, expressed the hope that “theologians, scholars and historians, animated by a spirit of sincere collaboration, will study the Galileo case more deeply and in loyal recognition of wrongs, from whatever side they come.”

In 1992, it was reported the Catholic Church had turned towards vindicating Galileo:

“Thanks to his intuition as a brilliant physicist and by relying on different arguments, Galileo, who practically invented the experimental method, understood why only the sun could function as the centre of the world, as it was then known, that is to say, as a planetary system. The error of the theologians of the time, when they maintained the centrality of the Earth, was to think that our understanding of the physical world’s structure was, in some way, imposed by the literal sense of Sacred Scripture…”

— Pope John Paul II, L’Osservatore Romano N. 44 (1264) – November 4, 1992

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