Lithuanian state dates to the 13th century, and it first established a border with Polish territories around the 14th century, after the destruction of the Old Prussian and Yotvingians tribes. Until that time most of contact between the two countries was limited to border military conflicts, such as Lithuanian raid on Duchy of Masovia in 1262, which killed Siemowit I of Masovia. This changed with a mid-1320s alliance between king of Poland, Władysław Łokietek, and Grand Duke of Lithuania, Gediminas. Gediminas daughter Aldona married Władysław Łokietek's son and future successor, Casimir III of Poland, in 1325, which led to improved relations. In 1358 a treaty between Duchy of Masovia and Grand Duchy of Lithuania outlined a border between the two for the first time. In 1385 the growing threat of the Teutonic Order to both countries led to a firmer alliance, the Union of Krewo, which signaled the beginning of a centuries-long Polish–Lithuanian union. This alliance was strengthened by the Polish-Lithuanian victory of the Teutonic Knights in the 1410 battle of Grunwald.