Astronomer and mathematician, born in Pisa, Italy. He entered Pisa University as a medical student in 1581, and became professor of mathematics at Padua (1592-1610), where he improved the refracting telescope (1610), and was the first to use it for astronomy. His bold advocacy of the Copernican theory brought severe ecclesiastical censure. He was forced to retract before the Inquistion, and was sentenced to indefinite imprisonment - though the sentence was commuted by the pope, at the request of the Duke of Tuscany. Under house arrest in Florence, he continued his research, although by 1637 he had become totally blind. Among his other discoveries were the law of uniformly accelerated motion towards the Earth, the parabolic path of projectiles, and the law that all bodies have weight. The validity of his scientific work was formally recognized by the Vatican in 1993.