Treasures of the Rare Books and Special Collections Library: Scientific works

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.