Dictionary of National Biography, 1885-1900/Ethelbert (d.866)
ETHELBERT or ÆTHELBERHT (d. 866), king of the West-Saxons and Kentishmen, the third son of Æthelwulf, bore the title of king in 853 (Kemble, Codex Dipl. p. 269), and probably about that time succeeded his eldest brother, Æthelstan, as under-king of Kent; his reign over that kingdom is, however, spoken of as beginning in 855, when his father left England on his pilgrimage (Asser). By Æthelwulf's will, Æthelred, his fourth, or third surviving, son, should have succeeded to the throne of Wessex on the death of Æthelbald, and Æthelberht should have remained king of Kent. This arrangement was, however, set aside, and on the death of Æthelbald in 860, Æthelberht succeeded to the West-Saxon kingship, and the kingdom of Kent was again united to the rest of southern England [see under Egbert]. In Æthelberht's days the Danes landed in Hampshire, and sacked Winchester, but were defeated by the forces of Hampshire and Wiltshire. Probably in the winter of 864–5 another band of pirates from Gaul took up quarters in Thanet, and the Kentishmen offered them money for peace, but while the peace lasted, though before the money was paid, they suddenly left their quarters and ravaged the eastern part of Kent. Æthelberht died in 866, after reigning five years over Wessex, and, according to Asser, ten years over Kent, and was buried by his brother Æthelbald at Sherborne. He is said to have been a peaceful, amiable, and noble king (Asser).
[Anglo-Saxon Chron., Asser, both in Mon. Hist. Brit.; Kemble's Codex Dipl. (Engl. Hist. Soc.).]