i understand it's everywhere, but i am more interested where it integrated with a martial practice. i have not encountered such practices in either vietnamese martial arts or the chinese ones that i knew of.
Looking up "warrior moks" in wikidpedia provided some possible avenues of research--
Tendai Budhhism and the Sohei
Various religious orders in medieval Europe such as the Teutonic Knights.
I don't much about any of the above, but they might be a good place to poke around.