After the battle the prelate sent a priest to Sverre with offers of peace; but the latter, who knew the treacherous character of his foe, would not treat with him, unless he appeared in person. He promised him safe-conduct, averring that he had other means of gaining fame than by killing a man like him. Nicholas made no response to this proposition; but instead of presenting himself before the king, hastened with his men overland to Nidaros, attacked the city, burned Sverre's fleet, which was lying in the fjord, and besieged the block-house, which finally fell by the treason of its commander, Thorstein Kugad. This was a severe blow to the king, and placed him in the subsequent contest at a great disadvantage. To meet the rebels on the sea with the small ships which were now left to him, was hazardous, as the battle of Thorsberg, near the mouth of the Drontheim fjord, during the following year plainly showed (1198). The Birchlegs were here worsted, in spite of their splendid bravery, and many of the king's staunchest friends and adherents were slain. Sverre hastened thence to Bergen, where the Bagler chief, Sigurd Jarlsson, in the meanwhile had been raging with fire and sword. He had burned those of Sverre's ships which he had found in the harbor, as well as the houses of the Birchlegs in the city, and he now laid siege to the block-house, where Queen Margaret was with all her household. As this rude fort was built of wood, his first intention was to fire it, and he began, for this purpose, to pile up wood for an enormous bonfire close to the walls. Sigurd Borgarklett, the commander of the fort, succeeded in lighting the wood-pile, before it was large enough to do any harm. The Baglers began to pile up wood once more, but again the besieged flung burning barrels of tar down upon them and drove them off. After many fruitless attempts, Sigurd Jarlsson gave up the plan of firing the block-house. [Illustration: THORGHÄTTEN, A FAMOUS ISLAND WITH A NATURAL TUNNEL, IN NORDLAND.]