Nicolaus Copernicus (19 February 1473-24 May 1543) was a Polish astronomer who is most famous for developing the theory that the Sun is the center of the universe. Born in Torun, Royal Prussia in 1473, he graduated from the University of Krakow. He was a lifelong bachelor, and he studied in both his native Poland and Italy, studying as a priest while making his first discoveries; he graduated from the University of Krakow in 1494 and studied in Italy for over ten years. In 1503, he returned to Poland after studying in Italy, and he became a polymath, studying astronomy, canon law, math, physics, economics, and diplomacy. In 1517, he developed the quantity theory of money, followed by the Gresham's law in 1519. His works Small Commentary (1514) and On the Revolutions of the Heavenly Spheres (1543) are his best-known works, as they proved Ptolemy's geocentric model wrong. He died in Frombork, Prince-Bishopric of Warmia in 1543.