A high king is a king who holds a position of seniority over a group of other kings, without the title of emperor. Similar titles include great king and king of kings. The high kings of history usually ruled over lands of cultural unity; thus high kings differentiate from emperors who control culturally different lands, and feudal monarchs, where subordinates assume lesser positions. High kings can be chosen by lesser rulers through elections, or be put into power by force through conquest of weaker kingdoms. High kingship In history and literature, high kings may be found where there is a high degree of cultural unity, along with sufficient political fragmentation that the high king's subordinates style themselves kings. In this respect, high kingships frequently differ from empires, which are culturally as well as politically heterogeneous, as well as from feudal monarchies, where the subordinate rulers take lesser titles (such as duke or count) and may be, at least in theory, subject to appointment and dismissal by the sovereign. In this model, a high king might be chosen from among a group of kings in his personal capacity, for instance by election or on the basis of genealogical superiority. Alternatively, the high kingship might be attached to the kingship of one of the constituent kingdoms, either permanently or when one kingdom is able to assert supremacy over the others. The high king's authority over other kings is usually limited, and in some high kingships his duties are largely ceremonial or restricted to occasions such as war that create a need for a unified command structure. Historical high kings Rulers who have been termed "high king" (by their contemporaries or by modern observers) include: Various rulers of the ancient and early medieval kingdoms in Great Britain and Ireland have been called "High King"; the High King of Ireland (), such as Brian Boru. the High King of Scotland (), like the legendary Macbeth. the King of the Britons, such as the legendary King Arthur, Uther Pendragon, and possibly Vortigern, have been termed "High King of Britain." the ruler of the Picts. the "Bretwalda" was essentially the high king of the Anglo-Saxons, though the name is rarely translated as such. some ancient Greek rulers, such as Agamemnon (see anax) the most powerful king of the various Etruscan city-states Mepe-Umaglesi (most high king) was a predicate of the Georgian Orthodox Mepe-Mepeta (king of kings)