King Knut could not, with his extensive possessions, devote much time to the government of Norway. He therefore had his son Sweyn proclaimed King of Norway in his stead. Sweyn's mother, who accompanied him to his new kingdom, was Aelgifa, the daughter of an ealdorman in Northampton. The Norsemen, however, called her Alfifa, and her son Sweyn Alfifasson. This was, accordingly, what the chiefs had gained by their rebellion—to be openly governed by the mistress of a foreign king and a boy who was and could be nothing but a tool in her hands. It was a humiliation which they could ill brook. If Alfifa had had the faintest comprehension of the people whom she undertook to govern, she might possibly for a time have maintained her son upon the throne; but when she proceeded to remodel the Norse legislation in the feudal spirit, she struck a blow at the very men who were the main-stay of her power. What the chiefs had desired was local independence—the right to manage their own affairs with as little interference as possible. They had hoped to obtain this liberty under a king who was too far away to trouble them. But now came Sweyn, and with him a number of Danes who became very important personages, and induced the king to modify the Norse laws so as to bring them more nearly into conformity with the laws of Denmark. It was then enacted that no one should have the right to leave the country without the king's permission, and that confiscation of property should be the punishment for transgression. Man-slaying was likewise to be punished by confiscation. So also an inheritance coming to an outlawed man should go into the king's treasury. Ships, fisheries, pasture-land, nay, even the peasant's hearthstones were taxed, and a system of extortion was instituted which was galling to the spirit of free men. Even the Christmas gifts which the peasants were to give the king, were fixed by law. The chief end of government seemed to be to transfer money from the people's pockets to those of the king. It was even asserted, though there was no law to that effect, that during Sweyn's reign the testimony of one Dane was sufficient to invalidate that of ten Norsemen.

The central principle in this legislation was the feudal idea that all land belonged to the king, and that the possessors, as his tenants, had to pay for the usufruct. It was the same appropriation by the king of all allodial rights, which was encountered for the first time during the reign of Harold the Fairhaired.

Alfifa, whom the people regarded as the author of the odious enactments, may have had her share in them; but far less than was popularly supposed. It was, no doubt, Knut who meant to crush the rebellious spirit of the Norse chiefs, by which he had himself profited, and Sweyn and Alfifa were merely his agents.

Under these circumstances it was but natural that the chieftains began to repent of their rebellion against King Olaf. Einar Thambarskelver, who prided himself on his absence from the battle of Stiklestad, was especially active in awakening regret among the TrÖnders at his death, and indignation at the rule of the Danes. He sent for Bishop Grimkel, who was living as an exile in Sweden, and agreed with him upon a plan of action. The bishop sent for the peasant Thorgils, who revealed the spot where he had buried the king. Permission was obtained from King Sweyn to bring the corpse to Nidaros, where it was placed in a splendid sarcophagus and interred under the altar in the Church of St. Clement (Aug. 1031). Although nearly a year had elapsed since the first burial, it was asserted that there was no trace of decay on the body and that the hair and the nails had grown. Einar and the bishop, at all events, encouraged such reports, and they grew in number and minuteness of convincing details. Grimkel now declared Olaf to be a saint, and Sweyn and Alfifa, though they raised many objections, dared no longer profess their disbelief. The 29th of July was set apart for the commemoration of his martyrdom. For the first time in their history the Norsemen felt themselves as one nation, united in their indignation against their foreign rulers and in their regret and veneration for the martyred king.

If Sweyn and Alfifa were aware of the sentiment with which they were regarded, they chose to ignore it. They were, however, not prepared for open defiance, and the events of 1033 must have taken them by surprise. In that year, a young man calling himself Tryggve, and professing to be a son of Olaf Tryggvesson and his wife Gyda, came from England or Ireland with a band of warriors and claimed the throne of Norway as his inheritance. Sweyn called upon the chiefs to aid him in punishing the pretender, but Einar Thambarskelver, Kalf Arnesson, and many other magnates, refused to follow him. With those who still recognized his authority the king sailed southward and defeated Tryggve in a short battle in Sognesund. On his return he and Alfifa met the TrÖnders at the thing and listened to their complaints, but could give them no satisfaction. Then Einar Thambarskelver said aloud and in the hearing of many: "I was not a friend of King Olaf; but the TrÖnders proved themselves to be poor merchants when they sold their king and got in his place a mare with her colt. The king cannot speak, and his mother only wishes what is bad and has the power to do it."

Alfifa rose to speak, but she could get no hearing. Einar Thambarskelver taunted her openly, and so hostile was the sentiment that she dared not take him to task. A sense of insecurity took possession of the king, and he and his whole household left TrÖndelag and took up their abode in the southern part of the country. His authority had practically ceased, though in name he yet remained king. In 1034, Einar Thambarskelver, Kalf Arnesson, and several other chiefs started for Russia and invited Magnus, King Olaf's only son, to return with them and become king of Norway. They asked and received his forgiveness for their hostility to his father, and swore to be faithful to him and to shield him from all harm. Magnus, who was then ten years old, accompanied them back to his native land, and was received with enthusiastic homage at Oere-thing, where he was proclaimed king. Sweyn and Alfifa made vain efforts to raise an army, but as no one heeded their summons, were forced to flee to Denmark. Here Sweyn died in the year 1036. As his father, Knut, had died in 1035, his half-brother, Harthaknut, became the heir to his claim to Norway, and, as we shall see, soon took measures to enforce it.