Earldom of Northumbria
The kingdom of Northumbria ceased to exist in 927, when it was incorporated into England as an earldom by Athelstan, the first king of a united England. In 937, Athelstan's victory over a combined Norse-Celtic force in the battle of Brunanburh secured England's control of its northern territory.
The Scottish king Indulf captured Edinburgh in 954, which thenceforth remained in possession of the Scots. His successors made repeated attempts to extend their territory southwards. Malcolm II was finally successful, when, in 1018, he annihilated the Northumbrian army at Carham on the Tweed, and Eadulf the earl of Northumbria ceded all his territory to the north of that river as the price of peace. Henceforth Lothian, consisting of the former region of Northumbria between the Forth and the Tweed, remained in possession of the Scottish kings.
The term Northumberland was first recorded in its contracted modern sense in 1065 in an entry in the Anglo-Saxon Chronicle relating to a rebellion against Tostig Godwinson.
Read more about this topic: History Of Northumberland