The Battle of the Trent was a battle fought at an unspecified site near the River Trent

River Trent

The River Trent is one of the major rivers of England. Its source is in Staffordshire on the southern edge of Biddulph Moor. It flows through the Midlands until it joins the River Ouse at Trent Falls to form the Humber Estuary, which empties into the North Sea below Hull and Immingham.The Trent...

 within the Kingdom of Lindsey

Kingdom of Lindsey

Lindsey or Linnuis is the name of a petty Anglo-Saxon kingdom, absorbed into Northumbria in the 7th century.It lay between the Humber and the Wash, forming its inland boundaries from the course of the Witham and Trent rivers , and the Foss Dyke between...

, in the ninth year of Ecgfrith's reign (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...

). The battle was fought between the 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...

n army of King Ecgfrith

Ecgfrith

Ecgfrith is the name of several Anglo-Saxon kings in England.* Ecgfrith of Northumbria, died 685* Ecgfrith of Mercia, died 796...

 and the Mercian army of Æthelred, king of 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...

. Æthelred defeated Ecgfrith, ending Northumbrian domination of the area. Lindsey remained part of Mercia until the Viking invasion of the ninth century.

Bede notes that the eighteen year old subking, Ælfwine of Deira, was killed in the battle, and that this almost led to further conflict between the two kingdoms, requiring the intervention of 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....

, 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...

.

In his account of the battle, Bede

Bede

Bede , also referred to as Saint Bede or the Venerable Bede , was a monk at the Northumbrian monastery of Saint Peter at Monkwearmouth, today part of Sunderland, England, and of its companion monastery, Saint Paul's, in modern Jarrow , both in the Kingdom of Northumbria...

 recounts the tale of a Northumbrian thegn

Thegn

The term thegn , from OE þegn, ðegn "servant, attendant, retainer", is commonly used to describe either an aristocratic retainer of a king or nobleman in Anglo-Saxon England, or as a class term, the majority of the aristocracy below the ranks of ealdormen and high-reeves...

 called Imm or Imma, who may have been the founder of the settlement of Immingham

Immingham

Immingham is a town in North East Lincolnshire, located on the south bank of the Humber Estuary...

. Imma was captured by the Mercians and, proving troublesome, was sold into slavery to a Frisian merchant who, when his identity was discovered, then ransomed him to one of the kings of Kent .