Nicolaus Copernicus was born on 19 February 1473 in the city of Toruń, in the province of Royal Prussia, in the Crown of the Kingdom of Poland. His father was a merchant from Kraków and his mother was the daughter of a wealthy Toruń merchant. Nicolaus was the youngest of four children. His brother Andreas became an Augustinian canon at Frombork, his sister Barbara became a Benedictine nun. His sister Katharina married the businessman and Toruń city councilor Barthel Gertner and left five children, whom Copernicus looked after to the end of his life. Copernicus never married or had children.

Completing his studies in University of Kraków and University of Padua 30-year-old Copernicus returned to Warmia, where he would live out the remaining 40 years of his life, apart from brief journeys to nearby cities. Copernicus was his uncle's - Lucas Watzenrode the Younger, Prince-Bishop of Warmia - secretary and physician from 1503 to 1510 and resided in the Bishop's castle at Heilsberg, where he began work on his heliocentric theory.
Some time before 1514, Copernicus wrote an initial outline of his heliocentric theory known only from later transcripts. It was a succinct theoretical description of the world's heliocentric mechanism, without mathematical apparatus; but it was already based on the same assumptions regarding Earth's triple motions.

Copernicus' major theory was published in De revolutionibus orbium coelestium (On the Revolutions of the Celestial Spheres), in the year of his death, 1543. In 1551, eight years after Copernicus' death, astronomer Erasmus Reinhold published the Prussian Tables, a set of astronomical tables based on Copernicus' work. Astronomers and astrologers quickly adopted it in place of its predecessors.