Battle of Heavenfield The Battle of Heavenfield was fought in 633 or 634 between a Northumbrian army under Oswald of Bernicia and a Welsh army under Cadwallon ap Cadfan of Gwynedd . The battle resulted in a decisive Northumbrian victory . The " Annales Cambriae " ( Annals of Wales ) record the battle as " Bellum Cantscaul " in 631 . Bede referred to it as the Battle of " Deniseburna " near " Hefenfelth " . Background . An alliance between Cadwallon of Gwynedd and King Penda of Mercia had led to an invasion of Northumbria . This was an odd alliance between a Christian king of British descent and a pagan king of Saxon descent . 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 . Cadwallon ' s army laid waste to Northumbria . Eanfrith , who had been exiled under Edwin , became king of Bernicia , whilst Deira was ruled by Osric , a cousin of Edwin . Eanfrith ' s reign was short , as he was killed by Cadwallon whilst trying to negotiate peace . According to Bede , Osric was killed by Cadwallon whilst trying to besiege him . Eanfrith ' s brother , Oswald , then returned from seventeen years exile in Dál Riata to claim the crown of Northumbria . However the threat of Cadwallon lingered and Oswald had to raise an army as soon as possible to deal with his invading force . The battle . It seems that the Welsh army advanced northward from York along the line of Dere Street . Oswald , who may have been accompanied by a force of Scots , took up a defensive position beside the Roman Wall , about four miles north of Hexham . It was claimed that the night before the battle , Oswald had a vision of Saint Columba , in which the saint foretold that Oswald would be victorious . 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 . According to Bede , Oswald raised a cross , and prayed for victory alongside his troops . It is believed that the Welsh had greater numbers , but they were forced to attack from the east along a narrow front , where they were hemmed in and unable to outflank the Northumbrians . It is not known how long the battle lasted or what the losses were , but the Welsh line finally broke . This began a headlong flight southward by the Welsh , pursued by the vengeful Northumbrians . Many Welsh soldiers were cut down as they ran , and according to Bede , Cadwallon was caught and killed at a place called the ' Brook of Denis ' , now identified as the Rowley Burn . The battle was a decisive victory for Oswald , and it was likely that the Welsh losses must have been substantial . Afterwards , the site was known as Heavenfield ( Hefenfelth ) . Aftermath . After the battle , Oswald re - united Deira with Bernicia and became king of all Northumbria . Bede believed that the importance of the battle was that it restored Christianity to Northumbria . Oswald was only to spend eight years upon the Northumbrian throne before he was defeated and killed by King Penda of Mercia at the Battle of Maserfield , in Shropshire . Oswald was succeeded as king of Northumbria by his brother Oswiu . The site today . The road east of Chollerford that runs alongside the Roman Wall ( B6318 ) has a stone cross standing alongside it to mark site of the Battle of Heavenfield . On the hill to the north of the cross stands a church marking the spot where Oswald was believed to have raised his battle standard . GoogleMap References . Sadler , John . " Battle for Northumbria " , 1988 , Bridge Studios , ( pages 25 – 29 ) ISBN 0 - 9512630 - 3 - X Marsden , John . " Northanhymbre Saga " , 1992 , Kyle Cathie Limited , ( pages 113 - 117 ) ISBN 1 - 85626 - 055 - 0