High King

A High King is a king who holds a position of seniority over other kings.

Possibly the best known example lies in the Ard Ri of Celtic Ireland, although the authority here tended to be more ceremonial than actual (except within the king's own native realm). In practice this meant that only claimants from the stronger clans had the opportunity to wield any real power over other sub-kings.

Another, more idealised, instance, was that of Prester John, who claimed authority over many kings, but declined any higher rank hismelf.