An Anglo-Saxon kingdom and later earldom formed from the joining of Bernicia and Deira. This at times was all of England north of the Humber, north to the Firth of Forth and across to the west of Scotland acquiring land through treaty and force. These bits of land were also variously lost. It was also an Early Medieval earldom when acknowledgement was made of the English and Scottish crowns - though retained considerable powers till the Harrying of the North.
To explore more glossary entries click on a letter.