Ceolwulf I was King of Mercia, East Anglia and Kent, from 821 to 823. He was the brother of Coenwulf, his predecessor, and was deposed by Beornwulf. William of Malmesbury declared that, after Cœnwulf: "the kingdom of the Mercians declining, and if I may use the expression, nearly lifeless, produced nothing worthy of historical commemoration." Actually, Mercia did have a moment of glory that William was unaware of. Indicating the year 822, the Annales Cambriae states: "The fortress of Degannwy (in Gwynedd) is destroyed by the Saxons and they took the kingdom of Powys into their own control."