The astronomer Nicolaus Copernicus was born on February 19, 1473 in Thorn. His father, Nikolas Koppernigk, died very early. Copernicus was then sent to his uncle, the Bishop Lukasz Watzenrode, who took him in and made possible a good education. He studied mathematics and astronomy in Cracow from 1491 until 1494, where he decided to latinize his name, signing from then on "Copernicus." He then went to Italy and studied medicine and law there. Copernicus received his doctorate in church law in 1503. He became more and more interested in geography and astronomy and less for theology, and he concentrated on the writings of the astronomer Ptolemy. He set down his perceptions of a new world system in writing from 1507 to 1517, in his "Commentariolus." Copernicus claimed that the sun was the center of our system, around which the planets moved in circular orbits. The earth was said to turn on its axis once a day and move around the sun in a year, as did all the other planets according to their own orbits. Copernicus returned to Poland, where he was employed as the personal physician and secretary of his uncle, who had been appointed the Bishop of Ermland in the meantime. After his uncle's death, he became the capitular of the cathedral in Frombork (Frauenburg) in 1512. Copernicus then concentrated on mathematics and astronomy, beginning his monumental work "De Revolutionibus Orbium Coelestium" ("On the Revolutions of the Heavenly Spheres"). This work was completed in 1530, and thereafter he turned his attention to a coinage reform; mathematics, especially trigonometry; his theories of the heavenly bodies. Copernicus' main work, "De Revolutionibus," was published shortly after his death in 1543. His theory of a heliocentric system was gradually accepted beginning in the late 17th century. Nicolaus Copernicus died on May 24, 1543 in Frombork.