From an Old English personal name, derived from ōs ‘god’ + weald ‘rule’. This was the name of two English saints. The first was a 7th-century king of Northumbria, who was killed in battle in 641. He was a Christian, a convert of St Aidan's, and his opponent, Penda, was a heathen, so his death was counted as a martyrdom by the Christian Church. The second St Oswald was a 10th-century bishop of Worcester and archbishop of York, of Danish parentage, who effected reforms in the English Church. The name was well established in northern England from the late 15th century, particularly in parishes where the church was dedicated to St Oswald. It enjoyed a modest revival in the 19th century as part of the vogue for pre-Conquest English names.