The history of Poland results from the migrations of Slavs who established permanent settlements on the Polish lands during the Early Middle Ages. In 966 AD, Duke Mieszko I of the Piast dynasty adopted Western Christianity; in 1025 Mieszko's son Boleslaw I Chrobry formally established a medieval kingdom. The period of the Jagiellonian dynasty in the 14th-16th centuries brought close ties with the Grand Duchy of Lithuania, a cultural Renaissance in Poland and territorial expansion that culminated in the establishment of the Polish–Lithuanian Commonwealth in 1569.