thelbert, d. 865, king of Wessex (860-65), son of Ęthelwulf. In 858 at the death of his father he ruled Kent, Surrey, Sussex, and Essex, and he reunited them with Wessex when in 860 he succeeded his brother Ęthelbald in that kingdom. Throughout his reign the attacks of the Danes were severe, and they continued through the reign of his brother and successor, Ęthelred. [The Illustrated Columbia Encyclopedia, 3rd ed., 1969]
King of Wessex 860-866, Under King of Kent 858-860. [ROWLEYHR.GED]
Additional information: Britannia.com