In 1385, the Grand Duke Jogaila accepted Poland's offer to become its king. Jogaila embarked on gradual Christianization of Lithuania and established a personal union between Poland and Lithuania. Lithuania was one of the last pagan areas of Europe to adopt Christianity. While territories to the north had been Christianized in 1186 by Western merchants and missionaries who formed the Order of the Brothers and the Sword to spread Christianity through military organization, the Lithuanians had defeated the Order's militant efforts in 1236.