 This alliance was strengthened by the Polish-Lithuanian victory of the Teutonic Knights in the 1410 battle of Grunwald.As Lithuania was increasingly threatened by the Muscovy (see Lithuanian-Muscovite Wars), it sought to strengthen its ties with Poland.The union reached an important milestone in 1569, when the Union of Lublin created a new federal state, the Polish–Lithuanian Commonwealth, which lasted until the Constitution of May 3, 1791 and partitions.