Birthright is a discontinued Dungeons & Dragons campaign setting based on the world of Aebrynis on the continent of Cerilia, in which the players took on the powers of the divinely-empowered rulers of nations, with emphasis on tactical gameplay. In 1996, Birthright won the Origins Award for Best Roleplaying Supplement of 1995. Birthright has informal d20 version.
The game revolves around the concept of bloodlines: divine power granted to heroes and passed to their descendants. Members of a bloodline create an aura of command known as Regency, which is measured in the game using regency points. Using regency, characters acquire a 'domain composed of provinces and holdings, and the development of these domains is as much a part of the game as development of the characters. The game uses three-month turns to model their actions in much the same way as it uses six-second rounds to model the characters' actions.