Bretwalda

Bretwalda (also brytenwalda and bretenanwealda) is an Old English word, the first record of which comes from the late 9th century Anglo-Saxon Chronicle. It is 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. It is unclear whether the word dates back to the 5th century and was used by the kings themselves, or whether it is a later, 9th-century, invention. The term bretwalda also appears in a charter of Æthelstan.

The rulers of Mercia were generally the most powerful of the Anglo-Saxon kings from the mid-7th to the early 9th centuries, but are not accorded the title of bretwalda by the Chronicle, which is generally thought to be because of the anti-Mercian bias of the Chroniclers. The Annals of Wales continued to recognize the kings of Northumbria as 'Kings of the Saxons' (i.e. the English) until the death of Osred I of Northumbria in 716.

Bretwëlde was a term used in 11th and 12th century Ireland to denote the 'high king'. Part of the Gaelic lexicon, this spelling suggests a Germanic (Saxon) origin, as the 'w' is most likely pronounced as a 'v'. It is also possible that the term derives from the Welsh Brit Gweldig, the term for a ruler of Britain.