Just to add my 2 cents on this. As for monks, it can easily be the wandering traveller (ala Kane from the original Kung-fu TV series). There was plenty of far east influence in Europe (are we forgetting the Silk Road that was around since Roman times?). Following the same styling, they could have been an escort of a caravan from a distant part that practices a previously unknown form of fighting. Simple explaination to the backstory.
I think this is kind of my problem. There is no good way to make the Monk feel a proper part of the environment, he always has to play the stranger in a strange land.