Interior of Villa del Gallo, once Galileo's residence, with two portraits of Galileo on the wall of a vaulted room. This is the place where Galileo lived under house arrest after his conviction by the Inquisition for heresy. Galileo Galilei (February 15, 1564 - January 8, 1642) was an Italian physicist, mathematician, astronomer and philosopher. Galileo was the first to successfully use a telescope to observe the heavens, discovering new stars, mountains on the Moon, and the phases of Venus. His discovery of moons that circled Jupiter, not the Earth, offered support for the controversial Copernican system that removed the Earth from the center of the Solar system. This brought Galileo into conflict with the Catholic Church. After writing his Dialogue on the Two Chief World Systems in 1632, he was tried and found guilty of heresy, forced to recant his views, and placed under house arrest for the rest of his life.