On this date in 1473, astronomer Nicolaus Copernicus (né Nicolaus Koppernigk) was born the youngest of four children in Torun, Poland. He studied a wide range of subjects, including philosophy, Latin, Greek, mathematics, law, medicine and astronomy, at the universities of Krakow, Bologna, Padua and Ferrara. His uncle, a bishop, strongly encouraged him to pursue a career in the church, since it would provide economic security, so he pursued a doctorate in canon law. His uncle helped secure him the position of canon at Frauenburg Cathedral in 1497, which provided a comfortable income and did not require much work. This allowed Copernicus the freedom to pursue other interests, such as economics, medicine, law, diplomacy, art and astronomy. A bishop later threatened to take away his income unless he entered the priesthood, but he continued to refuse. His opinion was so valued that the Fifth Lateran Council sought his views on calendar reform in 1514. Around this time, Copernicus began circulating his Little Commentary, criticizing the Ptolemaic system that placed the Earth at the center of the universe. Copernicus made astronomical observations without the aid of a telescope, which was not invented until 1609.
His most significant contribution to astronomy and science, De Revolutionibus Orbium Coelestium (On the Revolutions of the Celestial Spheres), postulated, against the view of the church at the time, a heliocentric universe, in which the Earth rotated on an axis around the sun each year. He completed this revolutionary book in 1530, and did not allow for its publication until 1541, at the urging of one of his admirers. Without Copernicus' permission, a preface was anonymously added right before publication, classifying the work as mere hypothetical speculation. (Johannes Kepler later publicized the identity of the preface's author, Andreas Osiander, a Lutheran pastor from Nuremberg.) Copernicus supposedly received the published book just before his death. Even though Copernicus dedicated his book to Pope Paul III, who had a fondness for astrology, in 1616 the book was placed on the Index of Prohibited Books (publications deemed immoral and impious by the Roman Catholic Church). In part, Galileo was condemned to house arrest and Giordano Bruno was executed for the heretical "Copernican" view that the Earth was not the center of the universe. D. 1543.