His travels took him to the court of Rædwald of East Anglia, who defeated Æthelfrith in 616, allowing Edwin to ascend the thrones of Bernicia and Deira.

After reigning for seventeen years, Edwin was defeated and killed in 633 at the Battle of Hatfield Chase by the combined armies of his supposed foster-brother Cadwallon ap Cadfan and the pagan Penda of Mercia.

The location of his early exile as a child is not known, but late traditions, reported by Reginald of Durham and Geoffrey of Monmouth, place Edwin in the kingdom of Gwynedd, fostered by king Cadfan ap Iago, so allowing biblical parallels to be drawn from the struggle between Edwin and his supposed foster-brother Cadwallon.

[5] Edwin was installed as king of Northumbria, effectively confirming Rædwald as bretwalda: Æthelfrith's sons went into exile in Gaelic kingdom of Dál Riata and Pictland.

That Edwin was able to take power not only in his native Deira but also in Bernicia may have been due to his support from Rædwald, to whom he may have remained subject during the early part of his reign.

There is firm evidence of a war waged in the early 620s between Edwin and Fiachnae mac Báetáin of the Dál nAraidi, king of the Ulaid in Ireland.

A lost poem is known to have existed recounting Fiachnae's campaigns against the Saxons, and the Irish annals report the siege, or the storming, of Bamburgh in Bernicia in 623–624.

[9] The routine of kingship in Edwin's time involved regular, probably annual, wars with neighbours to obtain tribute, submission, and slaves.

By Edwin's death, it is likely that these annual wars, unreported in the main, had extended the Northumbrian kingdoms from the Humber and the Mersey north to the Southern Uplands and the Cheviots.

[11] Edwin's realm included the former Roman cities of York and Carlisle, and both appear to have been of some importance in the 7th century, although it is not clear whether urban life continued in this period.

Apart from these events, the general character of Bede's account is one of an indecisive king, unwilling to take risks, unable to decide whether to convert or not.

King Edwin agrees and embraces Christianity; Coifi himself will set fire to the idols,[17] declaring "I will do this myself, for now that the true God has granted me knowledge, who more suitably than I can set a public example, and destroy the idols that I worshipped in ignorance?” Bede goes on to describe the scene as Coifi "formally renounces his superstitions, and asked the king to give him arms and a stallion."

[20] The brief speech by the unnamed counsellor, a nobleman, has attracted much attention; suggesting the "wisdom and hopefulness of the Christian message",[21] it has inspired poets such as William Wordsworth[22] and was called "the most poetic simile in Bede":[23] The present life man, O king, seems to me, in comparison with that time which is unknown to us, like to the swift flight of a sparrow through the room wherein you sit at supper in winter amid your officers and ministers, with a good fire in the midst whilst the storms of rain and snow prevail abroad; the sparrow, I say, flying in at one door and immediately out another, whilst he is within is safe from the wintry but after a short space of fair weather he immediately vanishes out of your sight into the dark winter from which he has emerged.

Furthermore, a definition of “peace” is to be understood as “freedom from robbery, rape, or violence; security to travel at will and to literally ‘go in peace.’”[25] Edwin's conversion and Eorpwald's were reversed by their successors, and in the case of Northumbria the Roman Paulinus appears to have had very little impact.

Very few Roman clergy were present in Paulinus's time, only James the Deacon being known, so that the "conversion" can have been only superficial, extending little beyond the royal court.

Edwin did not immediately respond to this insult, suggesting either that he felt unable to do so, or that Bede's portrayal of him as a rather indecisive ruler is accurate.

[27] From about 627 onwards, Edwin was the most powerful king among the Anglo-Saxons, ruling Bernicia, Deira and much of eastern Mercia, the Isle of Man, and Anglesey.

The imperium, as Bede calls it, that Edwin possessed was later equated with the idea of a Bretwalda, a later concept invented by West Saxon kings in the 9th century.

Of his two grown sons by Cwenburh of Mercia, Osfrith died at Hatfield, and Eadfrith was captured by Penda and killed some time afterwards.

They met their deaths in battle against similar foes, the pagan Mercians and the British, thus allowing both of them to be perceived as martyrs; however, Bede's treatment of Oswald clearly demonstrates that he regarded him as an unambiguously saintly figure, a status that he did not accord to Edwin.