After his death Deira was subject to 2Ethelfrith, king of Northumbria, until the accession of Edwin, in 616 or 617, who ruled both kingdoms (see EowiN) till 633.
After Oswald's defeat and death at the hands of Penda in 642 Bernicia fell to his brother Oswio, while Oswine son of Osric became king in Deira, though probably subject to Oswio.
At Gilling in 651 he caused the murder of Oswine, a relative of Edwin, who had become king of Deira, and a few years later took possession of that kingdom.
At his death in 633 the kingdom was again divided, Deira falling to his nephew Osric, while Bernicia was occupied by Eanfrith son of ZEthelfrith.
Bernicia was again separate from Deira under Eanfrith, son of lEthelfrith (633-634), after which date the kings of Bernicia were supreme in Northumbria, though for a short time under Oswio Deira had a king of its own.
Besides York, Yeavering and Maelmin in Bernicia, and Catterick in Deira, were the chief scenes of the work of Paulinus.
For a few years subsequently Deira was governed by lEthelwald son of Oswald.
He became earl of Deira after the death of Eadwulf Cutel, earl of Northumbria, about 1038, and earl of all Northumbria after murdering Eadwulf, earl of Bernicia, in 1041.
He is not mentioned, however, after 655, so it is probable that Deira was incorporated in the Bernician kingdom not long afterwards.
He married Acha, daughter of Ella (Ælle), king of Deira, whom he succeeded probably in 605, expelling his son Edwin.
He survived Oswald, and died shortly after the murder of his friend Oswine of Deira, on the 31st of August 651, in the 17th year of his episcopate.
His kinsman Osric succeeded in Deira, and Eanfrith the son of lEthelfrith in Bernicia.
His relationship to Edwin may have helped him to consolidate Deira and Bernicia.
On the seizure of Deira by 2Ethelfrith of Bernicia (probably 605), Edwin was expelled and is said to have taken refuge with Cadfan, king of Gwynedd.
Originally it comprised two independent kingdoms, Bernicia and Deira.
Osric the nephew of Edwin ruled Deira (6 33634), but his son Oswine was put to death by Oswio in 651.
Oswald reunited Deira and Bernicia, and soon raised his kingdom to a position equal to.
Oswine's death was compassed by Oswio in 651, and the throne of Deira was then obtained by 1-Ethelwald son of Oswald.
The districts north of the Humber contained two kingdoms, Bernicia (q.v.) and Deira, which were eventually united in Northumbria.
The first king of Deira of whom we know was Ella, or Aelle, who, according to Bede, was still reigning when Augustine arrived in 597.
The first Mercian king of whom we have any record was Cearl, who apparently reigned about the beginning of the 7th century, and whose daughter Coenburg married Edwin, king of Deira.
The pagan English of Deira (603) routed under lEthelfrith the Christian Scots of Argyll between Liddesdale and North Tyne; and pagan English for more than a century held unopposed the tianity.