King Æthelred I of Northumbria is murdered in Corbridge by a group led by his ealdormen, Ealdred and Wada. The patrician Osbald is crowned, but abdicates within 27 days.

Æthelred, was the king of Northumbria from 774 to 779 and again from 790 until he was murdered in 796. He was the son of Æthelwald Moll and Æthelthryth and possibly became king while still a child after Alhred was deposed.

Coria was a fort and town 2.5 miles (4.0 km) south of Hadrian's Wall, in the Roman province of Britannia. It was strategically located on the junction of a major Roman north–south road with the River Tyne and the Roman Stanegate road, which was also the first frontier line which ran east–west between Coria and Luguvalium. Corbridge Roman Site is in the village of Corbridge in the county of Northumberland.

Ealdorman was an office in the government of Anglo-Saxon England. During the 11th century, it evolved into the title of earl.

Osbald was a king of Northumbria during 796. He was a friend of Alcuin of York who often sent him letters of advice.

April 18 is the 108th day of the year in the Gregorian calendar; 257 days remain until the end of the year.