Derived from the Old English elements os "god" and weald "power, ruler". Saint Oswald was a king of Northumbria who introduced Christianity to northeast England in the 7th century before being killed in battle. There was also an Old Norse cognate Ásvaldr in use in England, being borne by the 10th-century Saint Oswald of Worcester, who was of Danish ancestry. Though the name had died out by the end of the Middle Ages, it was revived in the 19th century.