Seized power from Ceolwulf in 823. His ancestry is unknown, and his reign short but eventful. In 825 he fought Ecgberht of Wessex at Ellendun, near Swindon, and was badly beaten. This induced the smaller kingdoms of the south-east to throw off Mercian domination and ally with Wessex. To bring them to heel, Beornwulf advanced against the East Anglians, but was killed.
From The Kings and Queens of Britain in Oxford Reference.
Subjects: British History.