Renaissance is a setting agnostic set of d100 rules based on the MRQ/OpenQuest fork of BRP. It has a clean lean set of skills, a simple combat system and handles black powder weapons well.
There is support for optional magic, witchcraft in this case, and some creatures for a game with such beasties.
It has very good rules for Factions and this can be used to model political allegiances, religious groups, secret societies or Universities.
It is setting-less. So you can run Elizabeth, Medici, Colonial America easily.
There are some settings books:
Clockwork and Chivalry, which is the English Civil Wars, plus magic and clockpunk. Removing the magic and clockpunk is a work of moments, I have played it as a straight ECW game and it's excellent since all the political and religous factions are mapped out in the setting book.
There are some good (non fantasy) adventures set in the French-Indian Wars in Colonial America.
Dark Streets is a mid 18th Century Georgian England setting around a proto police force and the blind detective Henry Fielding.
My friend has run several Elizabethan scenarios with it, as have I, both straight, albeit my Kit Marlowe may have raised eyebrows..
It play straight, fast, but like all BRPs, deadly.. but that's fixable.
[There are also a Cthulthu version (d'oh) and a Fantasy Pirates and Dragons setting but you said you didn't want that]
Whenever I think modern black powder from 1450-1815 I think Renaissance, and frankly that actually is 1450-1870