Kingdom of Northumbria
Northumbria (Old English: Norþanhymbra Rīċe; in Latin: Regnum Northanhymbrorum) was one of the seven Anglo-Saxon kingdoms that existed between the early 7th century and the 10th century. Located in present-day northern England and southeastern Scotland, the kingdom's name derives from the Old English Norþan-hymbre, meaning "the people or province north of the Humber", as opposed to the southern people of the estuary of the Humber. Northumbria began to consolidate as a real kingdom in the early 7th century, when the two former central territories of Deira and Bernicia entered into a dynastic union. At its peak, the kingdom developed between the Humber and the Peak District and from the River Mersey in the south to the Firth of Forth (now Scotland) in the north. Northumbria ceased to be an independent entity in the mid-10th century when Deira was conquered by the Danes and gave birth to the Kingdom of York. The influential county of Bamburgh retained control of Bernicia for a period of time, until the area north of the Tweed was absorbed by the Kingdom of Scotland. The southern part of the Tweed merged into the Kingdom of England, specifically in the county of Northumberland and the palatine one of Durham.
Possible Celtic origins
The Anglo-Saxon kingdom of Northumbria originally consisted of two kingdoms roughly divided around the River Tees: that of Bernicia, north of the river, and Deira, to the south. It is possible that both regions originated as kingdoms made up of the Britons, a Celtic population that the Germanic colonists later subdued, although very little information is available on the society and culture of the British kingdoms themselves. Much of the inherent evidence comes from regional names that are British rather than Anglo-Saxon in nature. Also the names "Deira" and "Bernicia" could have the same origin, a circumstance which indicates that some toponyms did not disappear after the Anglo-Saxon migrations in Northumbria. There is also some archaeological evidence supporting the British origins of the political entities of Bernicia and Deira. In what would have been southern Bernicia, near the Cheviot Hills, a hill fortress in Yeavering called Yeavering Bell contains evidence that it had been a center of interest first to the Angles and then to the Saxons. The site was pre-Roman, dating back to the Iron Age around the 1st millennium BC. In addition to traces of Roman occupation, the site contains evidence of wooden buildings that predate Germanic settlement in the area, likely signs of British settlement. Brian Hope-Taylor has traced the origins of the name Yeavering, which seems deceptively English, to the British gafr referred by Bede regarding a town called Gefrin in the same area. Yeavering continued to form an important political center after the Anglo-Saxons began to settle in the north, as King Edvin had a royal palace in Yeavering.Overall, English place names dominate the landscape of Northumbria, suggesting the prevalence of an elite culture Anglo-Saxon at the time when Bede the Venerable, one of the most important historians of Anglo-Saxon England, was writing in the eighth century. According to Bede, the Angles ruled over the Germanic immigrants who settled north of the Humber and gained political importance during this time period. While the natives may have partially assimilated to the political structure of Northumbria, relatively contemporary textual sources such as Bede's Historia ecclesiastica gentis Anglorum describe relations between Northumbrians and Britons as difficult.
Unification of Bernicia and Deira
The Anglo-Saxon kingdoms of Bernicia and Deira often resulted in conflict before their future semi-permanent unification in 654. Political power in Deira was concentrated in one portion.