After the Romans withdrew in the early 5th century, Britain fragmented into numerous small kingdoms. By the 7th century Oswald’s Northumbria was one of the largest kingdoms in Britain. Northumbria consisted of two parts: Deira, centred on York, and Bernicia further north, including parts of current day Scotland. Oswald became king of Northumbria in 634 and focused power in Bernicia, with royal palaces at Yeavering, Mælmin (Milfield) and Bamburgh. In 635 Oswald appointed Aidan, an Irish monk from Iona, to be bishop of his kingdom and granting him the tidal island of Lindisfarne on which he founded Lindisfarne Priory.
Images c/o Wikimedia Commons:
1. Peoples of Britain c600 AD (image by Hel-hama, CC-BY-SA 3.0)
2. Kingdom of Northumbria in 802 AD (public domain image by Finn Bjorklid)