Oswald returned in 634 AD at the head of a small army and defeated King Cadwallon (who was ruling over Bernicia at the time), at the Battle of Heavenfield. Oswald reunited Northumbria and ruled as its king for eight years. Despite being the most powerful ruler in Britain at the time, he died on the 5th of August 642 AD at the Battle of Maserfield near present-day Oswestry (Oswald’s tree). He had been fighting the pagan Mercians of King Penda and it was recorded that he died praying for the souls of his soldiers that were dying around him. Later he was revered as a saint, as was common in the Middle Ages.
Oswald was instrumental in promoting the spread of Christianity in Northumbria. It is said that he was elevated to sainthood not because he achieved martyrdom by his death in battle but by extreme acts of generosity towards the poor during his life.
Oswald’s remains became scattered and were widely associated with miracles both in Britain and continental Europe. There are at least five claims to his head. Reginald of Durham recounts a miracle, saying that Oswald’s right arm was taken by a raven to an ash tree, which gave the tree ageless vigor. When the bird dropped the arm onto the ground, a spring emerged from the ground. Both the tree and the spring were, according to Reginald, subsequently associated with healing miracles.
In 909 AD, following a combined West Saxon and Mercian raid led by Æthelflæd, (the daughter of Alfred the Great), St Oswald’s relics were translated to a new minister in Gloucester, which was renamed St Oswald’s Priory in his honour.
His feast day is the 5th of August, the day on which he died.