Oswald was born , the son of King Athelfrith of Bernicia and his second wife Acha of Deira. At age twelve his father was killed in battle by Edwin who became King of Northumbria. Along with his brothers Eanfrith and Oswiu and their sister Aebbe, he found safety with the Scots in Dál Riata. The monks of Iona baptized the children and raised them in the Celtic Christian faith. For all of Edwin's reign Oswald remained in Exile. Cadwallon ap Cadfan, the Christian king of Gwynedd, along with the pagan Penda of Mercia, attacked Northumbria in 632. In 633 the two invading armies met Edwin at the Battle of Hatfield Chase. Edwin was killed and his army was destroyed. For the next year Cadwallon destroyed everything he could in Northumbria. At the same time Oswald was gathering a small army among the Scots and Picts.