In 1190, while the forces of the Third Crusade laid siege to the city of Acre, a group of crusaders from Bremen and Lübeck established a small field hospital under a ship's sail to care for some of the many sick and wounded among the Christian forces. In time this organisation grew into a major military order that would command vast resources, great estates and shape the history of the western world. Its members became known collectively as the Teutonic Knights.

As with every military order, the foundation of the Teutonic Hospital was a response to a specific need. The Templars were formed to help address the kingdom of Jerusalem's perennial shortfall of troops. The Hospitallers originated as a medical institution providing assistance for pilgrims visiting the city of Jerusalem. Over time, as such institutions grew in military and financial power, they were able to broaden the range of ‘needs’ to which they could respond. By the mid-twelfth century the Templars' military power had evolved to the point where they were able to contribute a major contingent to the field armies of the Latin East and to provide garrisons for a number of strongholds. The Hospitallers also developed a military arm and, in time, as both institutions received appeals from other realms, they provided warriors for many of Christendom's embattled frontiers.