Dunstan's retirement was soon followed by renewed Scandinavian invasions. After his death he was succeeded at Canterbury by Sigeric, who in 991 took a prominent part in purchasing peace from the Norwegian host. Although this was the beginning of a fatal policy, his action, taken by itself, seems capable of defence. It was a moment of pressing danger, and there was no force ready to meet the invader. Sigeric probably hoped that if the Norwegian fleet received payment it would defend the land from other piratical attacks. The invaders of England found shelter in the harbours of Normandy, and this led to a dispute between AEthelred and the Norman duke. War was prevented by the intervention of the Pope, the proper mediator between Christian princes. John XV. sent an envoy to England, and at his request a treaty was made between the king and the duke. Unfortunately, the peace with the Norwegians was broken. A fleet was fitted out for the defence of the coast; two bishops and two lay nobles were entrusted with the command, and, in spite of treachery, it gained one of the few successes of the reign. Two years later an invasion was made by the combined forces of Olaf of Norway, who, it is said, had already received Christianity from English missionaries, and of Swend, the apostate king of Denmark. After a time, AElfheah (St. Alphege), bishop of Winchester, was sent to treat for peace with Olaf, who was with his fleet at Southampton. The king listened to the bishop's exhortations, and fully accepted the faith into which he had been baptized. He met AEthelred at Andover, and there received confirmation, and promised never to return to England as an enemy. He kept his word, sailed away to evangelize his own dominions, and became one of the most heroic figures in early Scandinavian history. This bloodless victory won by the Church gave the land rest for three years, during which the Bernician see at last found an abiding-place. Fear of the Northmen drove Bishop Ealdhun and his monks to flee from Chester-le-Street. Taking the body of their patron with them, they sought shelter at Ripon, and in 995, when the immediate danger had passed, settled at Durham. There Ealdhun raised his church on the height above the Wear, in that strong place that has had so great an influence on the history of the see. Even in his time the bishopric began to assume its special character as a march against the Scots. [Sidenote: The Church and the witan.]