Ælfwine was the King of Deira from 670 to 679. He was a son of Oswiu of Northumbria

Oswiu of Northumbria

Oswiu , also known as Oswy or Oswig , was a King of Bernicia. His father, Æthelfrith of Bernicia, was killed in battle, fighting against Rædwald, King of the East Angles and Edwin of Deira at the River Idle in 616...

 and a brother of Ecgfrith of Northumbria

Ecgfrith of Northumbria

King Ecgfrith was the King of Northumbria from 670 until his death. He ruled over Northumbria when it was at the height of its power, but his reign ended with a disastrous defeat in which he lost his life.-Early life:...

.

After the succession of Ecgfrith as king of Northumbria

Northumbria

Northumbria was a medieval kingdom of the Angles, in what is now Northern England and South-East Scotland, becoming subsequently an earldom in a united Anglo-Saxon kingdom of England. The name reflects the approximate southern limit to the kingdom's territory, the Humber Estuary.Northumbria was...

 in 670, he made Aelfwine king of the sub-kingdom of Deira. Aelfwine was still a boy at the time, and the title may have been intended to designate him as the heir of the childless Ecgfrith. He was, however, killed in battle against the Mercia

Mercia

Mercia was one of the kingdoms of the Anglo-Saxon Heptarchy. It was centred on the valley of the River Trent and its tributaries in the region now known as the English Midlands...

ns at the Battle of the Trent

Battle of the Trent

The Battle of the Trent was a battle fought at an unspecified site near the River Trent within the Kingdom of Lindsey, in the ninth year of Ecgfrith's reign . The battle was fought between the Northumbrian army of King Ecgfrith and the Mercian army of Æthelred, king of Mercia. Æthelred defeated...

 in 679

679

Year 679 was a common year starting on Saturday of the Julian calendar. The denomination 679 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.- Deaths :* Æthelthryth, wife of King Ecgfrith of...

. Although his death could have led to an escalation of the war, further conflict was averted by the intervention of the Archbishop of Canterbury

Archbishop of Canterbury

The Archbishop of Canterbury is the senior bishop and principal leader of the Church of England, the symbolic head of the worldwide Anglican Communion, and the diocesan bishop of the Diocese of Canterbury. In his role as head of the Anglican Communion, the archbishop leads the third largest group...

, Theodore

Theodore of Tarsus

Theodore was the eighth Archbishop of Canterbury, best known for his reform of the English Church and establishment of a school in Canterbury....

, and King Æthelred of Mercia paid a weregild

Weregild

Weregild was a value placed on every human being and every piece of property in the Salic Code...

to Ecgfrith in compensation for Aelfwine's death. Bede describes Aelfwine as being about eighteen years old at the time of his death.