 Hartknoch was born in Jablonken (Jabłonka) near Ortelsburg (Szczytno) in the Duchy of Prussia.In 1650 the family moved to Passenheim (Pasym) and there witnessed the brutality and horrors of the Tatar attacks, fighting for the Kingdom of Poland, in southern Prussia.His life was saved by his teacher, who shoved him out the window.