 The existence of Oswald is known solely because of his coins.Coins and silver bullion were used throughout the period of the Viking attacks in East Anglia and the Vikings continued the Anglo-Saxon tradition of producing silver pennies, although at a reduced rate.Eight coins are known from the reigns of Æthelred and Oswald, whereas over two hundred are known to have been made by the moneyers of Oswald's predecessor, Edmund.