History of Poland during the Jagiellonian dynasty is the period in the history of Poland that spans the late Middle Ages and early Modern Era. Beginning with the Lithuanian Grand Duke Jogaila (Wladyslaw II Jagiello), the Jagiellonian dynasty (1386–1572) formed the Polish–Lithuanian union. The partnership brought vast Lithuania-controlled Rus' areas into Poland's sphere of influence and proved beneficial for the Poles and Lithuanians, who coexisted and cooperated in one of the largest political entities in Europe for the next four centuries.