Crusader Kings, released in 2004 by the Swedish studio Paradox Interactive, moved grand strategy in one specific direction: it stopped putting you in charge of a state and put you in charge of a person. You do not play France. You play a particular count, duke or king who has a spouse, children, personal traits, claims and vassals. When he dies you continue as his heir, and the heir's competence and legitimacy are different.

Everything distinctive about the game follows from that. The dynasty is the unit of play, so marriage politics matter as much as armies. Vassals hold their own interests, can revolt, and can press claims against your own lands. The papacy, church titles and crusades add further pressure from outside. The objective is not necessarily maximum conquest but keeping the bloodline on the throne across generations, a premise that grand strategy had not previously stated so directly.

Play runs in real time with pause, over a top-down map of medieval Europe. The player sets the speed, and reacting to a crisis without pausing is close to impossible. One or more players are supported, and in this kind of strategy multiplayer typically means long shared campaigns rather than short sessions.

The OldGame.cz entry keeps release data on its profile. The first Crusader Kings is now interesting chiefly as the origin point of the long line that grew from it. Many systems exist here in cruder form than in the sequels, but the central idea of playing a family rather than a country worked on the first attempt and has anchored the series ever since.