(M41) Scandinavian traditions contain some hints that of old the Swedish kings reigned only for periods of nine years, after which they were put to death or had to find a substitute to die in their stead. Thus Aun or On, king of Sweden, is said to have sacrificed to Odin for length of days and to have been answered by the god that he should live so long as he sacrificed one of his sons every ninth year. He sacrificed nine of them in this manner, and would have sacrificed the tenth and last, but the Swedes would not allow him. So he died and was buried in a mound at Upsala.(110) Another indication of a similar tenure of the crown occurs in a curious legend of the disposition and banishment of Odin. Offended at his misdeeds, the other gods outlawed and exiled him, but set up in his place a substitute, Oller by name, a cunning wizard, to whom they accorded the symbols both of royalty and of godhead. The deputy bore the name of Odin, and reigned for nearly ten years, when he was driven from the throne, while the real Odin came to his own again. His discomfited rival retired to Sweden and was afterwards slain in an attempt to repair his shattered fortunes.(111) As gods are often merely men who loom large through the mists of tradition, we may conjecture that this Norse legend preserves a confused reminiscence of ancient Swedish kings who reigned for nine or ten years together, then abdicated, delegating to others the privilege of dying for their country. The great festival which was held at Upsala every nine years may have been the occasion on which the king or his deputy was put to death. We know that human sacrifices formed part of the rites.(112) § 4. Octennial Tenure of the Kingship.