This doesn't need to be exact just in the ballpark.
Search terms: escorting a lady in wartime, number of men in a middle ages escort (hahahaha.... uh... no. Very much not the answers I was looking for :P), protecting a lady in middle/dark ages wartime, middle/dark age truce etiquette, middle/dark age wartime etiquette
None of my books seem to have anything applicable to this either.