The Warhammer world is based loosely on early Renaissance Europe, before the printing press, but with Elves, Dwarves, Halflings, Orcs, etc. The most detailed country is The Empire, which is based on Germany. All nations are on a pretty much constant state of war, as the insidious Chaos can strike at any time.
On the back of the Warhammer games, GamesWorkshop have been incredibly successful, growing from being the first reseller of TSR games in the UK to a FTSE 200 high-street chain. In a large part their success can be attributed to aggressive business practices, some of which kill the competition, and some of which milk their own fans to an extraordinary degree.
GamesWorkshop games (many of which not currently available, as they recycle games on a 4 year cycle to maximise revenue. WFB and W40K are always current):