Eardwulf was king of Northumbria from 796 until at least 806. Northumbria in the last years of the eighth century was the scene of dynastic strife between several noble families, and in 790, Æthelred I attempted to have Eardwulf assassinated. Æthelred himself was assassinated in 796. The reign of his successor Osbald lasted only twenty-seven days before he was deposed, and Eardwulf became king on 14 May 796. In 798 Eardwulf fought a battle at Billington Moor against a nobleman named Wada, who had been one of those responsible for King Æthelred 's death; Wada was defeated and driven into exile. In 801 Eardwulf led an army against Coenwulf of Mercia, perhaps because of Coenwulf 's support for other claimants to the Northumbrian throne.