Reading a history book without quotes is liking eating a hard-boiled egg without salt.
Having said that,I must add it not the size of the quote (I'm going to ignore the obvious parody of Mae West's famous line here) but how it is used. A seamless inclusion into the narrative is what is called for. It should clearly flow & add to the focus/direction of the chapter.
Much like you do in your "Tactics..." (sorry: don't own your "Salamanca"...yet).
BTW, IMO good history is well-written