Mikolaj Kopernik, or Koppernigk, who Latinized his name to Nicolaus Copernicus, was born in 1473, at Torun, in Poland. When he was ten years old, his father died, and his maternal uncle, Lukasz Watzenrode, later bishop of Warmia, became his guardian. In 1491, Copernicus matriculated at the University of Crakow, and in 1496 left for Italy, where he entered the University of Bologna. In 1501, he returned to Poland and became Canon of Frombork. In the summer of 1501, he returned to the University of Padua, and went on to Ferrara, where, in 1503, he took a Doctorate in Canon Law. In 1504 Copernicus settled at the Castle of Lidzbark, with his uncle Lukasz. In 1512, Copernicus finally moved to Frombork. Probably in those years, he wrote an unprinted booklet, the Brief Commentary, in which he explained the principles of his system. In 1540, his disciple Georg Joachim Rethicus (1514-1576) published the First Account, a short exposition of the heliocentric theory. Copernicus died in 1543, the same year of publication of his fundamental work, On the Revolutions of the Heavenly Spheres.