I can only say what I was told by the guide and what I saw by myself so forgive me if I'm wrong about the history or laction.
Fortress situated in the oldest part of Mombasa, near the smaller, older harbor. Lots of interesting things to see inside. Its history is as interesting as the place itself - many nations have been fighting over Fort Jesus throughout its 'life' and right now it belongs to Kenya, but it wasn't always so obvious...
In february it's just sooo hot inside Fort Jesus that you're gonna run around ruins to get a breathe of fresh air from those little windows in the walls facing the ocean...