The Order of Brothers of the German House of Saint Mary in Jerusalem, commonly known as the Teutonic Order, is a Catholic religious institution founded as a military society c. 1190 in Acre, Kingdom of Jerusalem. It was formed to aid Christians on their pilgrimages to the Holy Land and to establish hospitals. Its members have commonly been known as the Teutonic Knights, having a small voluntary and mercenary military membership, serving as a crusading military order for the protection of Christians in the Holy Land and the Baltics during the Middle Ages.