At the Battle of Hatfield Chase on 12 October 633, the invading Welsh and Mercians had killed Northumbrian king Edwin and Northumbria was split between its two sub-kingdoms, Bernicia and Deira.

[1] Eanfrith's brother, Oswald, then returned from seventeen years of exile, possibly including time spent in Dál Riata, to claim the crown of Bernicia.

Oswald placed his army so that it was facing east, with its flanks shielded by Brady's Crag to the north and the Wall to the south.

It is believed that the Welsh had greater numbers, but they were forced to attack from the east along the narrow front between the Wall and Brady's Crag, where they were hemmed in and unable to outflank the Northumbrians.

[3] Afterwards, due to the miraculous victory by Oswald's smaller force, the main battle site became known as Heavenfield (Heofenfeld) and became a place of pilgrimage for Christians at the time.

Adams posits that the battle began on the east bank of Devil's Water, moving to the ford at Peth Foot.