Bretwalda

Bretwalda is an Old English word meaning 'ruler of Britain'. It is only recorded in the late 9th-century Anglo-Saxon Chronicle entry for the year 829. 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.

The rulers of Mercia were generally the most powerful of the Anglo-Saxon kings from the mid 7th century to the early 9th century but are not accorded the title of bretwalda by the Chronicle, which had an anti-Mercian bias. The Annals of Wales continued to recognise the kings of Northumbria as "Kings of the Saxons" until the death of Osred I of Northumbria in 716.