Deira was a kingdom in Northern England during the 6th century AD. It extended from the Humber to the Tees, and from the sea to the western edge of the Vale of York. It later merged with the kingdom of Bernicia to the north to form the kingdom of Northumbria.

The name of the kingdom is of Brythonic origin, perhaps from Deifr, meaning "waters", or from Daru, meaning "oak", in which case it would mean "the people of the Derwent", a derivation also found in the Latin name for Malton, Derventio.

The first Anglian king of whom we have any record is Ælla, who flourished in the later 6th century after conquering the realm from the Britons in 581. After his death, Deira was subject to king Æthelfrith of Bernicia, who united the two kingdoms into Northumbria. Æthelfrith ruled until the accession of Ælla's son Edwin, in 616 or 617, who also ruled both kingdoms until 633.

Osric, the nephew of Edwin, ruled Deira after Edwin, but his son Oswine was put to death by Oswiu in 651. For a few years subsequently Deira was governed by Æthelwald son of Oswald of Bernicia.

Bede wrote of Deira in his Historia Ecclesiastica.

Further reading

• Geake, Helen & Joanthan Kenny (eds.) (2000). Early Deira: Archaeological studies of the East Riding in the fourth to ninth centuries AD. Oxford: Oxbow. ISBN 1-9001-8890-2
• Higham, N.J. (1993). The Kingdom of Northumbria AD 350-1100. Stroud: Sutton. ISBN 0-8629-9730-5