In spite of the insecurity of his position, King Olaf determined to celebrate Christmas in Nidaros, the town founded by Olaf Tryggvesson, and later known as Drontheim. The earls, caring little for commerce, had allowed this trading-post to go to ruin; and of its former prosperity there was scarcely a vestige left. Olaf, emphasizing here as ever his rôle as the legitimate heir of his great kinsman, began to repair the dilapidated houses and arranged himself as well as he could with his retinue. He might, however, have saved himself the trouble; for no sooner had he moved his goods up from the ships than Earl Sweyn and Einar Thambarskelver descended upon him in the night with 2,400 men, and would have made an end of his career, if his sentinels had not warned him in the nick of time of the impending danger. He made his escape southward to the Oplands, where he was again well received by his step-father. His one endeavor now was to raise an army large enough to crush his rival. Sigurd Syr's popularity and influence stood him in good stead, and many chieftains who had hitherto held aloof were induced to join him. Among these was Ketil Calf of Ringeness. The remainder of the winter was occupied in ship-building and in securing resources for a decisive campaign. It was at this time that the great galley "Karlshoved" (Churl's Head) was built, the prow of which was adorned with a man's head, which the king himself had carved. In the spring, as soon as the ice broke up, he sailed out of the Folden Fjord with about twenty ships and from 1,500 to 2,000 men.