Crusader Kings is a strategy-game with heavy RPG elements. You take control of a dynasty in medieval Europe right before the crusades started, at the time of Hastings. You can take control of some minor noble dynasty (like for example Hapsburgs) or an established dynasty (like Wilhelm the Conqueror & Co), and survive through centuries until the fall of Byzantium, rising the family to power. It is somewhat niche game, as you have to be a strategy-game geek *and* a roleplayer to really like the game, but if you are both, then there is no other game coming even close to Crusader Kings
From Wikipedia:
Crusader Kings is a grand strategy game made by Paradox Interactive about the period from December 26 1066 until December 30 1452. It was released in 2004. Unlike other past Paradox titles (Hearts of Iron, Victoria and the Europa Universalis series), Crusader Kings focuses on building a dynasty instead of a country, having similarities to role-playing games and even The Sims. The lead game programmer was Johan Andersson. As with the other Paradox Interactive history games, Crusader Kings must be considered a macro-management real-time strategy game (as moves are played out simultaneously and continuously) but typically involves far more planning than the fast-paced action that is usually associated with real-time strategy.
It is actually one of the few games I play in SP too, although CK really shines in MP
