The Gunhild-sons (or Eriks-sons) immediately returned to Norway when they received the message that Haakon the Good had named them as heirs to the throne. The oldest one, Harald Grayfell (Graafeld, so named after having once worn a gray fur robe), was considered as chief king, but their mother Gunhild was in fact the chief ruler. They were penurious and cruel, and soon became widely hated. There were many chiefs in the country at that time. Trygve Olafson, a grandson of Harald the Fairhaired, ruled in Viken, or the country around the Christiania Fjord; his cousin Gudrod, son of Biorn the Merchant, was chief in Westfold, and Earl Sigurd of Lade ruled the country around Throndhjem. Gunhild's sons at first resided mostly in the middle of the country, but soon laid plans to obtain more power. By great promises they bribed Griotgard, a brother of Earl Sigurd, to send them word when there might be a favorable opportunity to attack and kill the earl. This plan succeeded. Having been notified by Griotgard that Earl Sigurd was at a feast at Oglo in Stjoradal and had but few men with him, King Harald Grayfell and his brother Erling surrounded the house at night, set fire to the building, and burned the earl and all his men. When the people heard of Earl Sigurd's death, there was a great uprising. They gathered a large fleet, and, after having proclaimed Sigurd's son, Haakon, as their earl and commander-in-chief, they steered out of the Throndhjem Fjord, intent upon taking vengeance. When Gunhild's sons heard of this, they fled southward to Raumsdal and South More. Some time afterward the Gunhild-sons attacked and murdered Trygve Olafson, king in Viken, and Gudrod Biornson, king in Westfold. Harald Grayfell hastened to Trygve Olafson's home, hoping to be able to exterminate the whole race; but Trygve's widow, Astrid, had fled with her foster-father, Thorolf Lusarskeg. Gunhild's sons collected a great army in Viken and sailed northward, collecting men and ships on the way from every district for the purpose of fighting Earl Haakon. When Earl Haakon heard of this, he also collected men and fitted out ships, but when he ascertained the size of the approaching fleet, he sailed with a few men south to Denmark, where he was well received by King Harald Bluetooth (964). Gunhild's sons brought their army north to Throndhjem, and subdued the country and collected taxes, of which they had received none while Earl Haakon was there.