On Luther's advice the last Grand Master in Prussia dropped his vows in 1525, made the Order's state his hereditary duchy, and married

Albrecht of Brandenburg-Ansbach, a Hohenzollern, was elected Grand Master of the Teutonic Order in December 1510 and invested on 13 February 1511. In 1523 he asked Martin Luther for advice on the Order's statutes. Luther told him to drop the rule, marry, and turn Prussia into a secular principality. On 8 April 1525 the Treaty of Kraków made Prussia a hereditary duchy held as a fief of the Polish crown. Albrecht resigned as Grand Master and became a Lutheran. On 10 April, Easter Monday, he was invested with Prussia and received the homage of its estates. In 1526 he married Dorothea, daughter of the King of Denmark. Emperor Charles V put him under the imperial ban, which had no effect. Albrecht died at Tapiau on 20 March 1568. His son Albrecht Friedrich was mentally ill from youth, and the estates and Polish commissioners largely ran the duchy. When the son died in 1618, Prussia passed by inheritance contract to the Electors of Brandenburg. The Order kept its German and Austrian houses. Napoleon dissolved it outside Austria in 1809. Emperor Franz I re-founded it in 1834. It became a purely religious order in 1929. The Nazis banned it in 1938, and it regained its rights after the war. Its seat is in Vienna.