Ecgfrith of Northumbria

He ruled over Northumbria when it was at the height of its power, but his reign ended with a disastrous defeat at the Battle of Nechtansmere against the Picts of Fortriu in which he lost his life.

To secure his hegemony over other English kingdoms Oswiu arranged a marriage between Ecgfrith and Æthelthryth, a daughter of Anna of East Anglia.

In June 684,[6] Ecgfrith sent a raiding party to Brega in Ireland under his general Berht, which resulted in the seizing of a large number of slaves and the sacking of many churches and monasteries.

On 20 May, Ecgfrith was slain at the age of 40, having been lured by a feigned flight to the mountains, at what is now called the Battle of Dun Nechtain, located at either Dunnichen in Angus or Dunachton in Badenoch.

Like his father before him, Ecgfrith supported the religious work of Benedict Biscop in the kingdom and gave him 70 hides of land near the mouth of the River Wear in 674 to undertake the building of a monastery dedicated to St. Peter.

About ten years later, he made a second gift of land, 40 hides on the River Tyne at Jarrow, for the establishment of a sister house dedicated to St. Paul.