Earl Svein in the meanwhile collected a great force in the north. Many of the chiefs were his relatives and friends, and were able to give him great assistance. His brother-in-law, Einar Thambaskelfer, was on his side, and with him many other lendermen (a sort of local governors); and among them were many who had taken oath of allegiance to King Olaf the winter before. Earl Svein sailed south along the coast, drawing men from every district. When they came to Rogaland, Erling Skialgson of Sole joined them with a considerable force. Svein's fleet is said to have consisted of forty-five ships, with probably upward of 2,500 men; Olaf hardly had half the number of ships, but his ships were considerably larger, so that the number of men was probably about the same. Toward the end of Easter he entered Viken with his fleet and put in at Nesiar (Nesje), a headland on the east side of the bay (near Fredriksværn). On Palm Sunday, March 25, 1016, the two fleets met in battle. Before opening the battle Olaf had his ships tied together, his own ship, "Karlshoved," occupying a place in the centre. On this ship were one hundred and twenty men armed in coats of mail, French helmets, and white shields, on which was a gilt or painted cross. Olaf had a white banner on which the figure of a serpent was sewed. The king instructed his men to defend themselves with the shields in the beginning, and take care of their lances and arrows, so that they were not thrown away to no purpose. This advice was followed with good results. When the conflict had become exceedingly sharp, and the missiles began to be scarce on the earl's side, Olaf's men were well supplied, and their attack was very severe. Men fell in great numbers on both sides, but mostly on the earl's ships. King Olaf with the "Karlshoved" engaged Earl Svein's ship, and his men were soon preparing to enter it. The earl, seeing his defeat, ordered his ship cut loose from the others, and at the last moment his brother-in-law, Einar Thambaskelfer, succeeded in pulling the ship out of the line of battle from behind, using his own vessel as a tow-boat. When the earl's ship was gone, the flight became general. Some of the earl's men fled up the country, others surrendered on the king's mercy, but Earl Svein and his followers escaped out through the bay. Svein proceeded to Sweden to seek the aid of the Swedish king, while Erling Skialgson and some other chiefs sailed westward and returned to their homes. Earl Svein was well received by King Olaf the Swede, and it was agreed that next winter they should proceed with an armed force overland through Helsingland and Jemteland and down to the Throndhjem country, for the earl depended upon the faithful help of the people there. The summer was to be spent in viking expeditions in the Baltic. Svein made a cruise to Russia and plundered the coasts; in the fall he was taken sick there and died (1016).