Galileo Galilei, commonly known as Galileo, was a native of Pisa where he
became professor of mathematics. Here, from the study of falling bodies,
(dropping them off the leaning tower) he discovered the laws of dynamics.
In 1610, with the aid of his invention of the telescope, he discovered the
four moons of Jupiter and revolutionized the study of astronomy. He adopted
the Copernican theory of the solar system which he elaborated in his Siderius
Nuncius and other works. This brought him into conflict with the Inquisition
as the Church still espoused the Ptolemaic system.
In 1616, the Copernican theory was condemned at Rome and Galileo was forbidden
"to hold, teach, or defend it". The Church took a long time to act in the
case of Copernicus, some 73 years as De Revolutionibus was published in 1543.
This was probably due to a number of factors: Copernicus was a canon in a
monastery and he dedicated the book to Pope Paul III; it contained a preface
(later discovered by Kepler not to have been written by Copernicus) that
stated that the geocentric system proposed was only an hypothesis and made
no claims about how the universe was really consituted. But with Galileo's
writings, which reached out to a wide audience and brought the Copernican
arguement into the mainstream of educated discourse, the Church finally acted.
In 1632 Galileo broke silence and published the Dialogo.Though his works
represent one of the great turning points in the history of human thought,
in 1633 they were turned over to the Inquisition and banned by Pope Urban
VI as a heresy and a breach of good faith. Galileo was examined by the
Inquisition under threat of torture. He was sentenced to imprisonment and
to public recantation of his beliefs. His famous words "Eppur si muove" -
"None the less it does move" - are probably apocryphal. He was released after
a few months imprisonment
After his death in 1642, his common-law wife submitted his manuscripts on
telescopes and pendulums to her confessor who destroyed them as heretical
works. They were to remain on the Index of Prohibited Books until 1824.