Galileo Galilei was born on 15 February 1564 in Pisa, Italy. He came from a family that appreciated science, maths, the arts and above all music. Whilst at the University of Pisa, although not a good student (failed his degree in Medicine) he was a very good mathematician. At the early age of 25, Galilei was given the position of 'adjunct mathematics lecturer' in mathematics at the University of Pisa. In 1592 was given the opportunity of a chair of 'principal lecturer' at Padua, where he remained until 1610. He invented, among other things, the microscope; but his interests did not entirely lie with mathematics and mechanics - he turned more and more to physics and astronomy.
News of Hans Lippershey(1570-1619) method of grinding and polishing the lenses of his telescopes led Galileo to perfect and construct his own. Armed with this new telescope, Galileo made some of his most famous discoveries. On 7 January 1610 Galileo pointed his telescope towards Jupiter and discovered the moons of Jupiter and the phases of the planet Venus. There is actual written documentation of those observations by Galileo himself. Also in 1610 Galileo was nominated the foremost Mathematician of the University of Pisa which came with the title of Grand Duke of Tuscany.
There was strong opposition to Galileo's sympathy with Nicolaus Copernican's theory that the Earth and other planets revolved around the sun. In 1614 Father Tommaso Caccini denounced Galileo's theory, whereupon Galileo went to Rome to defend himself but was admonished by Cardinal Bellarmino because his theories went against the Church.
Finally in 1632 a tribunal passed sentence upon Galileo and he was compelled to denounce his theory and then exiled to Sienna. Eentually, in December 1633, he retired to his villa ' the Gioiello' in Arcetri. His health declined, he lost his sight and the loss of his daughter in 1634 left him bereft of support. Galileo died in 1642.