In 774, Æthelbert called a council which deposed Alhred the King of Northumbria and sent the ex-king north into exile with the Picts. The cause of the deposition may have been related to missionary work. The historian D. P. Kirby feels that Æthelbert was not a supporter of Alhred prior to his deposition. Alhred was replaced with Æthelred, who was replaced in 778 by Ælfwald, the son of Oswulf. Kirby sees Æthelbert's withdrawal of support as instrumental in the deposition of Æthelred, noting that Ælfwald was closely related to Æthelbert, unlike both Alhred and Æthelred. Kirby also notes that medieval chroniclers noted that Æthelbert is said to have not "spared evil kings".