778/9. Æthelbald and Heardberht kill three Northumbrian high-reeves
Æthelred of Northumbria driven out
Ælfwold, Oswulf's son, succeeds to Northumbria
December 25, 779. Northumbrian ealdorman Beorn burnt alive

The Anglo-Saxon Chronicle notes that in 778 Æthelbald and Heardberht killed three high-reeves, Ealdwulf, son of Bosa, at Coniscliffe (Durham), and Cynewulf and Ecga at Helathirnum (unidentified), on 22 March. Simeon of Durham dates these events to 29 September (perhaps the killings at Coniscliffe were in March and those at Helathirnum in September, or vice versa), and adds that it was done on the orders of Æthelred. Contemporary sources neither confirm nor deny this, but the fact that Ælfwold then succeeded to the kingdom and drove Æthelred from the country suggests that he was seen to be responsible. The Chronicle reports Ælfwold's accession under 778, while Simeon places it under 779, adding the information that Ælfwold was the son of Oswulf, who had been killed (probably at the instigation of Æthelred's father Æthelwold) in 758.

That Ælfwold's accession did not end the disputes is suggested from the fact that on December 25, 779, the ealdorman Beorn was burnt at Seletun (unidentified). This is all the information reported by the Chronicle; Simeon adds that Beorn was one of Ælfwold's nobles, and burnt by the ealdormen Osbald and Æthelheard, who led an army against him as well. This Osbald may well be the same as the one who was king of Northumbria for about a month in 796 after the death of Æthelred, and based on a letter from Alcuin he might have been involved in Æthelred's death as well (see under 796). The Ealdorman Æthelheard noted here may be the one whose death on August 1, 794, is reported in the Chronicle.

The Chronicle reports no more of the secular events of Ælfwold's reign, though we know from the report of the papal legates in 786 that they met with Ælfwold and his archbishop (see entry on 786), and the emphasis in the legatine canons on loyalty to the king should have been a welcome boost to Ælfwold's safety. Unfortunately he was killed two years later (see entry on 788).