Deira

Deira (Old English: Derenrice or Dere) was a kingdom (559-664 AD) in Northern England which probably emerged when Anglian warriors conquered the Derwent Valley in the third quarter of the fifth century. It extended from the Humber to the Tees, and from the sea to the western edge of the Vale of York. It was the southern of the two kingdoms of Deira and Bernicia which later merged 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.

According to Simeon of Durham (writing early in the 12th century) it extended from the Humber to the Tyne, but the land was waste north of the Tees. After the Brythonic kingdom centred on Eboracum, which may have been called Ebrauc, was taken by King Edwin, the city of Eboracum became its capital and was called Eoforwic ("boar-place") by the Angles.