Sweyn was scarcely out of Magnus' sight, before he made haste to justify Einar's apprehension. Having regained his father's fiefs and the power which they gave him, he called the Danish chieftains together at the _thing_ in Viborg, and was proclaimed King of Denmark. Magnus, incensed at his treachery, started with a large fleet to punish him; but Sweyn ran away, first to Sweden and later to the Wendic provinces along the Baltic. No opposition was, therefore, offered to Magnus, and after having chastised many who had acknowledged Sweyn as king, he started for Jomsborg, which had also rebelled against his authority. He stormed and destroyed the old viking nest, and killed and scattered its occupants. In the meanwhile an enormous army of Wends, among the chiefs of which was Sweyn Estridsson himself, was pouring in over Sleswick and met Magnus at Lyrskogs Heath (1043) where, in spite of their superior numbers, they were overwhelmingly defeated. It is told that 10,000 corpses covered the battle-field. The victory, which was in a large measure due to King Magnus' personal bravery, gained him a great prestige, and what was more, stemmed the tide of Slavonic migration in the North. If the Wends had then gained a foot-hold in Jutland, Denmark would probably to-day have been a Slavonic country, and the whole destiny of the Scandinavian North would have been changed. Magnus took up his winter-quarters in Sleswick; but no sooner had he dismissed part of his army than Sweyn was again in arms, and was defeated by Magnus in two naval battles at Aaros and Helgeness. In the spring of 1044, when Magnus was twenty years old, he returned to Norway. His fame filled the North; for so great things scarcely any king of his race had achieved at so early an age. In spite of his hot temper, he was well beloved by all his people; for with all his vehemence, he was upright, generous, and noble. A pleasant story is told of him, which throws much light upon his character. In Magnus' guard there was a high-born Icelander, named Thorstein, son of Side-Hall. Like most of his countrymen he was not amenable to discipline, and offended the king by going to Dublin without his permission. In return for this he was outlawed; but, relying upon his friends and family connections, he returned to Norway, paying no heed to the judgment of outlawry. He brought with him some fine stud-horses, and offered them as a gift to Einar Thambarskelver, whose influence with the king was known to be great. Einar declined them; but his son Eindride, not knowing of his father's refusal, accepted them with joy. He even invited Thorstein to be his guest for the winter and had the hardihood to bring him in his company to the king's Yule-feast. He was, however, persuaded by his father to return home with the outlaw, before the king had seen him. On the fourth day after Christmas, Einar, who was sitting at Magnus' side, ventured to put in a good word for Thorstein, to which the king answered: