EGFRITH (d. 685), king of Northumbria, succeeded his father Oswio in 671. He was married to Aethelthryth, daughter of Anna of East Anglia, who, however, took the veil shortly after Egfrith's accession, a step which possibly led to his long quarrel with Wilfrid archbishop of York. Egfrith married a second wife, Eormenburg, before 678, the year in which he expelled Wilfrid from his kingdom. Early in his reign he defeated the Picts who had risen in revolt. Between 671 and 675 Egfrith defeated Wulf here of Mercia and seized Lindsey. In 679, however, he was de feated by Aethelred of Mercia, who had married his sister Os thryth, on the river Trent. Egfrith's brother Aelfwine was killed in the battle, and the province of Lindsey was given up when peace was restored at the intervention of Theodore of Canterbury. In 684 Egfrith sent an unsuccessful expedition to Ireland under his general Berht. In 685 he led a force against the Picts, was lured into their mountain fastnesses and slain at Nechtanesmere (now Dunnichen) in Forfarshire. Bede dates the beginning of the decline of Northumbria from his death. He was succeeded by his brother Aldfrith.
See Eddius, Vita Wilfridi (Raine, Historians of Church of York, Rolls Series, 1879-94), 19, 20, 34, 39, 44; Bede, Hist. Eccl. (ed. Plummer, 1896), iii. 24, iv. 5, 12, 13, 18, 19, 21, 26.