Northumbria

Northumbria (Old English: Norþanhymbra / Norþhymbre) was a mediæval kingdom of the Angles, in what is now Northern England and South-East Scotland, becoming subsequently an earldom in a united Anglo-Saxon kingdom of England. The name reflects the approximate southern limit to the kingdom's territory, the Humber estuary.

Northumbria was formed by Æthelfrith in central Great Britain in Anglo-Saxon times. At the beginning of the 7th century the two kingdoms of Bernicia and Deira were unified. (In the 12th century writings of Henry of Huntingdon the kingdom was defined as one of the Heptarchy of Anglo-Saxon kingdoms.) At its greatest the kingdom extended at least from just south of the Humber, to the River Mersey and to the Forth (roughly, Sheffield to Runcorn to Edinburgh) — and there is some evidence that it may have been much greater (see map).

The later (and smaller) earldom came about when the southern part of Northumbria (ex-Deira) was lost to the Danelaw. The northern part (ex-Bernicia) at first retained its status as a kingdom but when it become subordinate to the Danish kingdom it had its powers curtailed to that of an earldom, and retained that status when England was reunited by the Wessex-led reconquest of the Danelaw. The earldom was bounded by the River Tees in the south and the River Tweed in the north (broadly similar to the modern North East England).

Much of this land was "debated" between England and Scotland, but the Earldom of Northumbria was eventually recognised as part of England by the Anglo-Scottish Treaty of York in 1237. On the northern border, Berwick-upon-Tweed, which is north of the Tweed but had changed hands many times, was defined as subject to the laws of England by the Wales and Berwick Act 1746. The land once part of Northumbria at its peak is now divided by modern administrative boundaries:

• North East England includes Anglian Bernicia
• Yorkshire and the Humber includes Anglian Deira and Celtic Elmet
• North West England includes Cumbria, though Cumbria was more of a Northumbrian colony with its own client kings for most of its history in the Early Medieval era
• Scottish Borders, West Lothian, Edinburgh, Midlothian and East Lothian cover the extreme north

Northumbria is also used in the names of some regional institutions: particularly the police force (Northumbria Police, which covers Northumberland and Tyne and Wear) and a university (Northumbria University) based in Newcastle. The local Environment Agency office, located in Newcastle Business Park, also uses the term Northumbria to describe its patch. Otherwise, the term is not used in everyday conversation, and is not the official name for the UK and EU region of North East England.