Edwin (alternately Eadwine or Æduini) (c. 584 - October 12, 633) was a King of Northumbria (616 - 633). He was the son of Aella of Deira and the brother of Aethelric of Deira. The name "Eadwine" is Old English for "wealthy friend".
Around the year 604, upon the seizure of Deira by his brother-in-law, Æthelfrith of Bernicia, Edwin was expelled and took refuge with the king of Gwynedd, Cadfan ap Iago. After the battle of Chester, in which Æthelfrith defeated the Welsh, Edwin fled to Raedwald, king of East Anglia. Aethelfrith offered Raedwald a bribe to kill Edwin, but Raedwald refused and defeated Ælthelfrith at the river Idle in about 616. Aethelfrith was killed, and Raedwald installed Edwin as king of Northumbria. The sons of Æthelfrith, among them Eanfrith, were driven out.
We have little evidence of Edwin's activity outside of Northumbria before 625. It is probable that the conquest of the Celtic kingdom of Elmet, located in the neighbourhood of modern Leeds and ruled by a king named Cerdic, occurred during this period. This may have led to the later quarrel with Cadwallon ap Cadfan, king of Gwynedd.
Edwin is said to have founded the city of Edinburgh in 626, and it is possible that the city was named after him (one interpretation of its etymology is "Edwin's fort"). He also seems to have annexed Lindsey to his kingdom by 625. In this year he entered negotiations with Eadbald of Kent to marry his sister Ælthelberg. It was a condition that Christianity should be tolerated in Northumbria, and accordingly Paulinus was consecrated bishop by Justus in 625, and was sent to Northumbria with Æthelberg.
According to Bede, Edwin was favourably disposed towards Christianity owing to a vision he had seen at the court of Raedwald, and in 626 he allowed Eanfled, his daughter by Æthelberg, to be baptized. On April 20, the day his daughter was born, an attempt was made on the king's life by Eomer, an emissary of Cwichelm, king of Wessex. Saved by the devotion of his thegn Lilla, Edwin vowed to become a Christian if victorious over his treacherous enemy. He was successful in the ensuing campaign, and gave up worshipping his traditional gods.
A letter of Pope Boniface V helped him decide, and, after consulting his friends and counsellors (one of whom, the priest Coifi, afterwards took a prominent part in destroying the temple at Goodmanham), he was baptized with his people and nobles at York, on Easter (April 11), 627. In this town he granted Paulinus a see, built a wooden church and began one of stone. Besides York, Yeavering and Maelmin in Bernicia, and Catterick in Deira, were the chief scenes of the work of Paulinus.
It was the influence of Edwin which led to the conversion of Eorpwald of East Anglia. Bede notices the peaceful state of Britain at this time, and says that Edwin used a standard like that carried by the Roman emperors. Bede tells us that Edwin conquered the Isle of Man and took Anglesey from Cadwallon ap Cadfan, who, according to the Annales Cambriae, Edwin besieged on the island of Glannauc (Priestholm, or Puffin Island). He was definitely recognized as overlord by all the other Anglo-Saxon kings of his day except Eadbald of Kent, and thus considered Bretwalda.
The defeated Cadwallon fled into exile, but he returned within a few years and reconquered his lost lands with the aid of Penda of Mercia. Their combined armies then invaded Northumbria and defeated Edwin at Hatfield Chase near Doncaster, killing him along with his son Osfrith. Another of his sons, Eadfrith, was captured by Penda and later executed. Edwin's body was hidden in the church of Edwinstowe.
Edwin's kinsman Osric succeeded him in Deira, and Eanfrith, the son of Æthelfrith, took power in Bernicia.
After his death, Edwin was regarded as a saint. Since Penda was a pagan, and Cadwallon "Christian only in name", Edwin was considered a martyr and Pope Gregory XIII allowed him to be depicted in the English College church at Rome.