Given your new reply and some of the clarifications to it I have three suggestions, although both only have one book out (with an exception) they are based on novels that you can incorporate for setting material or ignore as you see fit.
The first is A Game of Thrones. With significant alterations to the d20 system, this presents a fantasy version of the War of the Roses. While magic exists, its rare (indeed the magic rules are presented in a GM only section) but seems to be makign a comeback (according to the novels, in your campaign that can be another story). Publish by the now defunct Guardians of Order, the main book is an excellent resource for running a game set in George RR Martin's world or another of your making. I have been thinking about running a game with at least some of the rules but not the setting myself.
Second is The Black Company from Green Ronin based on the novels by Glen Cook. The magic system is unique and taxing so that spell casters are a viable option, but not at all common in the game world. Items are more likely to be various degrees of master work. There are some uber-powerful NPC spellcaster if you choose to use them, but there is no real need to do so.
FInally is Thieves World also from GR. I dont have personal experiance with these, but based on what you have said and the reviews I have read you may want to check it out.