Nicolaus Copernicus came from a middle class background and received a good standard humanist education, studying first at the university of Krakow (then the capital of Poland) and then travelling to Italy where he studied at the universities of Bologna and Padua. He eventually took a degree in Canon Law at the university of Ferrara. At Krakow, Bologna and Padua he studied the mathematical sciences, which at the time were considered relevant to medicine (since physicians made use of astrology). Padua was famous for its medical school and while he was there Copernicus studied both medicine and Greek. When he returned to his native land, Copernicus practised medicine, though his official employment was as a canon in the cathedral chapter, working under a maternal uncle who was Bishop of Olsztyn (Allenstein) and then of Frombork (Frauenburg).
While he was in Italy, Copernicus visited Rome, and it seems to have been for friends there that in about 1513 he wrote a short account of what has since become known as the Copernican theory, namely that the Sun (not the Earth) is at rest in the center of the Universe. A full account of the theory was apparently slow to take a satisfactory shape, and was not published until the very end of Copernicus's life, under the title On the revolutions of the heavenly spheres (De revolutionibus orbium coelestium, Nuremberg, 1543). Copernicus is said to have received a copy of the printed book for the first time on his deathbed. (He died of a cerebral haemorrhage.)
Copernicus's heliostatic cosmology involved giving several distinct motions to the Earth. It was consequently considered implausible by the vast majority of his contemporaries, and by most astronomers and natural philosophers of succeeding generations before the middle of the seventeenth century. Its notable defenders included Johannes Kepler (1571 -1630) and Galileo Galilei (1564 - 1642). Strong theoretical underpinning for the Copernican theory was provided by Newton's theory of universal gravitation (1687).