King of the Northumbrian kingdom of Bernicia (Northumbria) (633–42). He gained the kingdom after his victory near Hexham over the Welsh king Cadwallon (633), who had in the previous year invaded Northumbria and killed Oswald’s uncle Edwin. Following that invasion Oswald took refuge on Iona, where he became a Christian. On his return he arranged for missionaries from Iona, led by St Aidan, to convert his people (635). Oswald was killed in battle by the pagan king Penda of Mercia.