King of Northumbria from 634 until his death, and was venerated as a saint in the Middle Ages.

Oswald was the son of Æthelfrith of Bernicia and came to rule after spending a period in exile; after defeating the British ruler Cadwallon ap Cadfan, Oswald brought the two Northumbrian kingdoms of Bernicia and Deira once again under a single ruler, and promoted the spread of Christianity in Northumbria.

He was given a strongly positive assessment by the historian Bede, writing a little less than a century after Oswald’s death, who regarded Oswald as a saintly king; it is also Bede who is the main source for present-day historical knowledge of Oswald. After eight years of rule, in which he was the most powerful ruler in Britain, Oswald was killed in the Battle of Maserfield.    from Wikipedia