The first settlement in the vicinity of Toruń is dated by archaeologists to 1100 BC (Lusatian culture). During early medieval times, in the 7th through 13th centuries, it was the location of an old Slavonic settlement, at a ford in the Vistula river. In the 10th century it became part of the emerging Polish state ruled by the Piast dynasty. In 1677 the Prussian historian and educator Christoph Hartknoch was invited to be director of the Thorn Gymnasium, a post which he held until his death in 1687. Hartknoch wrote histories of Prussia, including the cities of Royal Prussia.