Galileo moved to Florence in 1610 to become mathematician to the Grand Duke of Tuscany. He left the University of Padua, where he had taught mathematics since 1592, for a prestigious court appointment under Cosimo II de' Medici.
The position combined the titles of court mathematician and philosopher with a professorship at the University of Pisa. Crucially, Galileo was not required to lecture regularly in Pisa, giving him more time for research, writing and demonstrations. His appointment followed the publication of Sidereus Nuncius in 1610, which described his telescopic observations of the Moon, Jupiter's moons and other celestial features.
Galileo's move is sometimes confused with his earlier relocation to Padua or with his later move to Arcetri. Florence became his intellectual and political home, but the appointment also brought him closer to the Medici court and to the religious controversies that later surrounded his defence of heliocentrism.