In Dungeons & Dragons monks are “members of an Order” who “seek both physical and mental superiority in a religious atmosphere.” (Arneson 1975:1) A path originally open to the cleric, the monk had complete control over both mind and body: he was immune to mental powers, could simulate death, and use a dreaded attack known as the “quivering palm” to kill his opponents with a mere touch.
The origin of the word “monk” comes from the late Greek “monachos,” which means a solitary person or hermit. This in turn came from the Greek word “monos” which means alone. It passed into Latin as “monachus,” to Old English as “munuc” and then into English as monk. Monks then, live alone (Ayto 1990:353.
Monks first appeared in the Men & Magic supplement. Clerics with the right combination of attributes could become monks — implying a religious calling for the monk class. Monks were ascetics, limiting their acquisition of treasure and items. In return, they could fight with their bare hands to stun opponents, simulate death, heal themselves through force alone, and resist mental intrusion. The pinnacle of the monk’s power was the quivering palm (Arneson 1975:1).
In the first edition of Oriental Adventures, Gygax explained that Brian Blume, who was inspired by fictional martial arts style Sinanju (made popular by the Destroyer series of novels), created the monk class. Sinanju bestowed abilities upon its practitioners that bordered on the fantastic, including the ability to climb walls, dodge bullets, outrun a car, etc. (Gygax 1986). All of these powers figure strongly in the monk class.
And yet, the monk is one of the few classes that have no anchor in Western lore. Crusading knights encountered the assassins, but the monk is a particularly Eastern phenomenon. As a result, the monk’s roots were sometimes conflated, such that one set of lead miniatures had Franciscan-style monks posed in martial arts stances.
This description is a rough draft from my upcoming book, The Evolution of Fantasy Role-Playing Games.