- brȳtenwalda, brȳtenwealda, brētenānwealda
First attested in the 9th century, but applied to kings who ruled from the 5th century onward. From an adjective brytten (“wide”) and walda (“ruler, wielder”).
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.