Cynewulf was the King of Wessex from 757 until his death in 786. He ruled for about 29 years. He was a direct male descendant of Cerdic. Cynewulf became king after his predecessor, Sigeberht, was deposed. He may have come to power under the influence of Æthelbald of Mercia, since he was recorded as a witness to a charter of Æthelbald shortly thereafter. However, it was not long before Æthelbald was assassinated and as a consequence, Mercia fell into a brief period of disorder as rival claimants to its throne fought. Cynewulf took the opportunity to assert the independence of Wessex: in about 758 he took Berkshire from the Mercians. Cynewulf was also often at war with the Welsh.