Copernicus, Nicolas. Founder of the modern system of astronomy. Copernicus was born in 1473 at Thorn, Prussia. Studied at Cracow and Bologna, and became professor of mathematics at Rome. Obtaining a canonry in the chapter of Frauenburg, Copernicus there wrote his work in Latin, "On the Revolution of the Celestial Orbs," which he deferred publishing until a little before his death in 1543, aware of the opposition it would arouse.