A monarch is the person at the head of a monarchy. This is a form of government in which a state or polity is ruled or controlled by an individual who typically either inherits the throne by birth or who is elected monarch and who typically rules for life or until abdication. Monarchs may be autocrats (absolute monarchy) or ceremonial heads of state who exercise little or no power or only reserve power, with actual authority vested in a parliament or other body (constitutional monarchy).