The Order of Brothers of the German House Saint Mary in Jerusalem (Official names: Latin: Ordo domus Sanctæ Mariæ Theutonicorum Hierosolymitanorum, German: Orden der Brüder vom Deutschen Haus St. Mariens in Jerusalem), or for short the Teutonic Order, is a German Roman Catholic religious order of the Holy Roman Empire. It was formed to aid Catholics on their pilgrimages to the Holy Land and to establish hospitals to care for the sick and injured. Its members have commonly been known as the Teutonic Knights, since they also served as a crusading military order during the Middle Ages. The membership was always small and whenever the need arose, volunteers or mercenaries augmented the military forces.