Following the successful takeover of York by the Vikings in 866/7, southern Northumbria became part of the Danelaw, but in the north English rulers held on from a base at Bamburgh.
Uhtred was murdered in 1016, and king Cnut then appointed Erik, son of Hakon, earl at York, while Eadwulf succeeded at Bamburgh.
[5] In one twelfth-century Durham source, De obsessione Dunelmi, Ealdulf is described as "a very lazy and cowardly man", who ceded Lothian, the northern part of Bernicia, to the Scots—though the historicity of this claim is disputed, one of several twelfth-century English accounts that try to explain the 'loss' of Lothian to Scotland.
[6] Another twelfth-century tradition relates that Lothian had been under Scottish control since the time that King Edgar ceded it to Kenneth II of Scotland in the early 970s.
[7][8] [9] Recently, it has been argued that Lothian remained part of the principality of Bamburgh until its dissolution around 1090, during the reign of Malcolm III.