Whats the name of the strategy game?

in the game, you are a nation and you develop your nation to obtain certain goals. things i can remember: you can be called on a crusade involuntarily and if you accept you go to war with a heathen nation, but if you reject, the pope gets mad at you and catholic countries will become your enemy. also i know the king eventually pes away and you have to marry in other kingdoms to gain heir to your kingdom or you will loose