Nicholas Copernicus (1473-1543)

Born in Torun, Poland, in 1473, Copernicus first studied astronomy and astrology at the University of Cracow (1491-94). Through his uncle, Lukas Watzenrode (1447-1512), who later became the bishop of Varmia (Ermland), he was elected a canon of the cathedral chapter of Frombork (Frauenburg). As part of his requirement as a canon, he matriculated in 1496 in the University of Bologna to study both canon and civil law. There, he lodged with and worked as an assistant to Domenico Maria the Ferrarese of Novara (1454-1504), professor of mathematics and astrology and also the official compiler of prognostications for the university. After briefly returning to Frombork, Copernicus studied medicine at the University of Padua (1501-3) and then moved on to the University of Ferrara where he obtained a doctorate in Canon Law (1503). He then returned to Varmia, where he was based for the rest of his life. He acted as medical advisor and secretary to his uncle at Heilsberg, and was later heavily involved with the administrative tasks in the diocese of Frombork.
In 1514, the Lateran Council sought Copernicus's opinion on calendar reform. Around the same time, he began to circulate in manuscript the 'Commentariolus' (A Brief Description), in which he criticised the current Ptolemaic system for not adhering to the principle of uniform circular motions and offered instead his own system in which the earth and all the other planets rotate around the sun.

By the 1530s, Copernicus's reputation as a skilled mathematician had even reached the ears of the Pope. A professor of mathematics at the University of Wittenberg, Georg Joachim Rheticus (1514-1574) who was on a tour of visiting distinguished scholars, visited Copernicus in 1539. Copernicus shared his ideas with him, and Rheticus published the Narratio Prima (First Report on the Books of Revolution) in 1540 at Gdansk, in which he reported Copernicus' heliostatic theory in an astrological framework: the changing fortunes of the kingdom of the world, according to Rheticus, depended on the changing eccentricity of the sun. Following the favourable reception of the Narratio Prima, Rheticus persuaded Copernicus to publish a full account. This, of course, became the De Revolutionibus Orbium Coelestium (On the Revolutions of the Heavenly Spheres), published in March 1543 at Nuremberg. Copernicus died two months later. Copernicus is often portrayed as a revolutionary figure who advocated a heliocentric system, overthrowing existing systems and institutions. Yet, his monumental work, the De Revolutionibus, is far from a revolutionary manifesto for modern astronomy. Copernicus is known to have carried out many observations (though he explicitly mentions only about 27), and none seems to have been crucial for formulating his theory. The work follows closely the structure of Ptolemy's Almagest, it is based on parameters and data from Ptolemy, and his dedication to the Pope is written in a fashionable style. He does indeed provide a model of the universe in which the earth and all the other planets orbit around the sun and the earth acquired a daily rotation, but the sun itself was not quite in the center of that universe. He established the order of planets and devised a system which accounted for the movements of planets without equants, but he was motivated by the desire to establish uniform circular motion, itself a classical ideal. Copernicus certainly believed that this was the true system of the physical universe, but this conviction was not shared widely by his