Albert (Ger. Albrecht), the first duke of Prussia, son of Frederick, margrave of Anspach and Baireuth, and grandson of Albert Achilles, elector of Brandenburg, born May 17, 1490, died March 21, 1568. He was educated for the church under the elector of Cologne, but also served in the army of the emperor Maximilian, and in 1511 was elected grand master of the Teutonic order. Refusing to take the oath of fealty to the king of Poland, he became involved in the hostilities which had subsisted for years between the order and the Poles. Sigismund I. of Poland, whose sister was Albert's mother, began the war in earnest, but, after some successful fighting, was in 1521 induced to grant a four years' truce, during which Albert solicited aid from other German princes. He betook himself to Germany, where he was persuaded by Luther to embrace the reformation and change the domains of the order into a temporal principality. At the expiration of the truce the grand master consented to hold the territory of the order as a fief from Poland, and the majority of the knights agreed to hold under Albert. Albert now threw himself heartily into the reformation movement, established new schools, and founded the university of Konigsberg. Dissensions on doctrinal points between the professors of his new university involved him in troubles which lasted till his death.