Answer:
Diarchy
Explanation:
Diarchies are a form of government in which the leadership is shared by two heads of state. In most diarchies, the diarch maintains his position for life and passes on his responsibilities and powers to his children or family members when he dies. The diarch is one of the oldest forms of government and has been for several centuries. Diacles have been known since Antiquity, having been present in Sparta, Rome, Carthage, as well as in Dacian and Germanic tribes. Several ancient Polynesian societies had this political structure.
