Anglo-Saxon kingdom of Britain.
Located between the River Humber and the Firth of Forth, it extended from the Irish Sea to the North Sea. Its religious, artistic, and intellectual achievements in the 7th8th centuries were epitomized by such centres as Lindisfarne and the monasteries of Wearmouth and Jarrow. Jarrow, with its fine library, was the home of the Venerable St. Bede . After Northumbria's expansion in the 7th century, it became the most powerful of the Anglo-Saxon kingdoms before being destroyed by the Danes, who captured York in 866. In 944 the last Scandinavian ruler of York was expelled, and Northumbria became an earldom within the kingdom of England.