Nicolaus Copernicus Nicolaus Copernicus was born on 19 February 1473 in the city of Toruń (Thorn), in the province of Royal Prussia, in the Crown of the Kingdom of Poland.1 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 (Andrew) became an Augustinian canon at Frombork (Frauenburg). His sister Barbara, named after her mother, became a Benedictine nun and, in her final years, prioress of a convent in Che?mno (Kulm); she died after 1517.[4] 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. 1 Jump up to: a b Sheila Rabin. "Nicolaus Copernicus". Stanford Encyclopedia of Philosophy. Retrieved 22 April 2007.