The Knights Templar were founded before 1125 to defend Jerusalem, and the Knights Hospitaller (also called the Knights of St. John) were founded in 1144 to aid and protect Christian pilgrims who had travelled to Jerusalem.
These knights wore special garments to identify them and were not allowed to marry. They did not own any personal property, but lived together in houses owned by their order. The knights of both orders were supposed to lead a life of prayer, combined with military training and fighting for their religion.
[Original author: Toria Forsyth-Moser, 2002-3]