From Middle English.
bretwalda (plural bretwaldas)
- (historical) A title given to some of the rulers of Anglo-Saxon kingdoms from the 5th century onwards who had achieved overlordship of some or all of the other Anglo-Saxon kingdoms.
The original meaning of the title is thus "wide-ruler", but it was reinterpreted, likely at an early period predating its 9th-century attestation, as containing the name Britain and understood in the sense of "ruler of Britain". The title rex Britanniae "king of Britain" is used by Æthelbald of Mercia in 736, who at the same time is also recorded as a bretwalda.