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.