In the Anglo-Saxon period, the Humber River was a major boundary of the weald, separating Northumbria from the southern kingdoms. Indeed the name Northumbria simply indicates the area North of the Humber. It currently forms the boundary between the East Riding of Yorkshire, to the north and North and North East Lincolnshire, to the south. East Anglia was defeated by the Mercians three times. Bernicia covered lands north of the Tees, whilst Deira corresponded roughly to modern-day Yorkshire.

After Edwin's death, Northumbria was split between Bernicia, where Eanfrith, a son of Aethelfrith, took power, and Deira, where a cousin of Edwin, Osric, became king. Cumbria tended to remain a country frontier with the Britons. Both of these rulers were killed during the yeare that followed, as Cadwallon continued his devastating invasion of Northumbria. Oswald backed warriors sent by Domnall Brecc of Dál Riata, defeated and killed Cadwallon at the Battle of Heavenfield in 634. He subsequently expanded his kingdom considerably and incorporated Gododdin lands northwards up to the Firth of Forth and also gradually extended his reach westward, encroaching on the remaining Cumbric speaking kingdoms of Rheged and Strathclyde. Northumbria became not only part of modern England's far north, but also covered much of what is now the south-east of Scotland. King Oswald re-introduced Christianity to the Kingdom, but this time, by appointing St Aidan, an Irish monk from the Scottish island of Iona to convert his people. This led to the introduction of Celtic Christianity, as opposed to Roman Catholicism. A monastery was established on Lindisfarne, probably as an echo of the island monastery of Iona.

Cumbric was the Brythonic Celtic language centred in Cumbria, and spoken from southern Lowland Scotland south as far as Greater Manchester, i.e. the area anciently referred to as Y Gogledd Hen, Tameside, Ashton, Northampton. Cumbric was once referred to as North Welsh and Cornish as South, or West, Welsh. Cumbria is neighboured by Northumberland, County Durham, North Yorkshire, Lancashire, and the Lieutenancy areas of Dumfries and Roxburgh, Ettrick and Lauderdale in Scotland. The boundaries are along the Irish Sea to Morecambe Bay in the west, and along the Pennines to the east. Cumbria's northern boundary stretches from the Solway Firth along the border with Scotland to Northumberland. Carlisle is a city in the extreme northwest of England, some 16 km from the border with Scotland. It is part of the City of Carlisle local government district, and acts as the administrative centre for both the district and Cumbria. It is the traditional county town of Cumberland.

1 2