The Knights Templar were the first monks to actually take vows to fight. Their original purpose was to guard pilgrims to and from Jerusalem. They became the most elite fighting force of the middle ages.
The Templar Order consisted of Knight Brothers that were of noble lineage who wore the white surcoats and cloaks. However the Order also has Sergeants who were of non-noble blood who outnumbered the knight brothers 20-1. These Brothers wore black surcoats and cloaks with the Templar red cross.