Galileo (Galileo Galilei (Pisa 1564- Arcetri 1642) was the father of Modern Science. Professor of Mathematics in the University of Pisa since 1589, he moved to Padova and back to Pisa in 1611. He conceived and stated the scientific method, and was equally gifted for experiment, theory and publication of the results. He also tried to measure the speed of light and built the first astronomical telescope, becoming the founder of modern Astronomy. His Sidereus Nuncius (1610) is also a literary masterpiece for its clear and very readable style. When he reported the discovery of the Pianeti Medicei (Jupiter’s moons) and of the sunspots he was suspected of heresy. The foundations of Mechanics are in his Discorsi e dimostrazioni matematiche intorno a due nuove scienze, attinenti alla meccanica ed ai meccanismi locali, Leiden (1636). The book was published abroad because of the persecutions by the Church, whose teaching was contrary to any motion of the Earth. He avoided the stake thanks to his prudence and to good relations with the catholic hierarchy. He was a friend of Pope Urbano VIII Barberini. Nevertheless he was taken to trial, forced to retract and imprisoned for the rest of his life in Arcetri. Thereafter, life was very hard for scientists in Italy for quite a long time) contradicted all the ancient wisdom and doctrine when he established the principle of inertia, clearly stated the principle of Relativity and measured the acceleration of gravity and the circular motion around the year 1600.