... Before starting on his voyage Ine had made over his crown to his distant kinsman Aethelheard, who was also the brother of his wife Aethelburh.  But the succession was not undisputed; an aetheling named Oswald, a descendant of another branch of the house of Ceawlin, also aspired to the throne; probably he was some relative of the Ealdbert and Cynewulf whom Ine had slain, and was supported by their faction.  He kept up civil war for two years, till Aethelheard slew him in 730.  By this strife all the work of the last thirty years was undone, and Wessex lost its predominance in the South and sank very low.  It was, no doubt, Aethelheard's misfortunes which tempted Aethelbald of Mercia to fall upon him. (England Before the Norman Conquest, Oman, 1910)