Frederick George Meeson Beck, 1911 Encyclopædia Britannica, Volume 7… (1911)
“ York was the capital of its kings. The date of its first settlement is quite unknown, but the first king of whom we have any record is Ella or Ælle, the father of Edwin, who is said to have been reigning about 585. After his death Deira was subject to Æthelfrith, king of Northumbria, until the accession of Edwin, in 616 or 617, who ruled both kingdoms (see Edwin) till 633. Osric the nephew of Edwin ruled Deira (633–634) , but his son Oswine was put to death by Oswio in 651. For a few years subsequently Deira was governed by Æthelwald son of Oswald. ”
