king of the West Saxons, or Wessex (from 643), son of Cynegils. Though his father became a Christian, Cenwalh himself long remained a pagan. Soon after his succession he discarded his wife, sister of King Penda of Mercia, who retaliated by making war and driving Cenwalh into exile (645–648). While in exile in East Anglia he was baptized and, on his return to the throne in Wessex (648), built St. Peter's in Winchester. Throughout much of his reign, he fended off his enemies, the Welsh and the Mercians. The Mercians seized the Isle of Wight, southern Hampshire, and all the West Saxon lands north of the Thames from Cenwalh. In the west Cenwalh did have military successes, however, notably when he drove the Britons to the River Parret in 658. His wife Seaxburg (or Seaxburh) apparently reigned for about one year after his death.