Born into a prosperous family, Nicolaus Copernicus attended the University of Krakow and later the universities of Bologna, Padua, and Ferrara at the beginning of the 16th century. He returned to the cathedral at Frauenberg, where he was a canon of the church, practiced medicine, wrote a treatise on monetary reform, and began serious study of astronomy. By May 1514, he had completed a draft of his theory of Earth and other planets revolving about a sun, which challenged dogma dating back to Aristotle and Ptolomy. With his radical reordering of the structure of the universe, he stayed with the ancient beliefs of perfect circular motion of heavenly bodies. Copernicus' heliocentric theory marked the beginning of the scientific revolution and of a new view of a greatly enlarged universe.