Order of Teutonic Knights

German religious and military order. Founded by Lübeck and Bremen merchants during the siege of Acre in the Third Crusade and confirmed by Pope Clement III in 1199, it soon became an important order in Germany. After aiding Hungarian King Andrew II in repulsing the Cumans, the knights were invited by Polish Duke Conrad of Masovia to help crush the heathen Prussians. Frederick II named Grandmaster Hermann of Salza (1209-39) a prince of the empire in 1226 and authorized the acquisition of East Prussia. The Teutonic Order began the conquest in 1231, sponsored large-scale colonization by German peasants and merchants during the next century, and transferred its residence to the fortress Marienburg in 1309.

The order failed to unite its East Prussian and Livonian holdings and declined in the face of Polish, Lithuanian, and Russian resurgence. After the defeat at Tannenberg (1410) and a series of subsequent military disasters, the Treaty of Thorn (1466) reduced its territory to a portion of East Prussia. Grandmaster Albert of Hohenzollern (1490-1568) accepted Lutheranism in 1525 and secularized it as the duchy of Prussia under the suzerainty of the Polish king. Those remaining Catholic transferred the seat to Mergentheim in Franconia, and some participated in the Turkish wars. Although Napoleon dissolved the order in Germany in 1805, its existence continued in Austria with an archduke as grandmaster until 1918. It received a new Rule in 1929 establishing its strictly religious character, and the order now works chiefly in schools and hospitals.