Background Styrbjörn the Strong was the son of the Swedish king
Olof Björnsson, who had died by poisoning; Styrbjörn suspected his uncle
Eric, his father's co-king, of being responsible. Denied the crown by the Swedish
Thing, he had made himself the ruler of the
Jomsvikings but wanted to amass an even greater force in order to take the crown. Styrbjörn's method was to pillage far and wide in the newly created kingdom of
Denmark until its king
Harald Bluetooth asked for a settlement. Harald gave Styrbjörn his daughter
Tyra as his wife and Styrbjörn went away, but he then returned to Denmark with 1000
longships and forced the Danes to give him 200 additional ships and whoever among them he saw fit to take with him, including the king himself. He then set sail for Sweden with his armada.
Battle When King Eric learned that the navy had entered
Mälaren, he sent the
fiery cross in all directions and amassed the
leidang at
Uppsala.
Torgny the Lawspeaker advised him to block the waterway leading to Uppsala with a palisade of stakes. When Styrbjörn's navy arrived and saw that they could not sail further, Styrbjörn vowed never to leave Sweden, but to win or die. To encourage his men to fight to the death, he set the ships on fire. Styrbjörn's forces marched towards Uppsala. When the Swedes attempted to stop their advance in the forest, he threatened to start a forest fire, and this convinced the Swedes to let him and his men pass. Þorgnýr told King Eric to tie together cattle and harness them with spears and swords. When the enemy approached on the
Fýrisvellir plain,
thralls pushed the herd towards the Jomsvikings, which caused havoc among their ranks. However, Styrbjörn was an excellent warchief and restored order. The fight lasted all that day and the next without either side gaining the upper hand, even though King Eric had received large reinforcements. According to
Styrbjarnar þáttr Svíakappa, during the second night, Styrbjörn sacrificed to
Thor, but later a red-bearded man appeared in his camp and spoke a
skaldic verse declaring that he was angry at being disturbed by Styrbjörn and foretelling defeat. Eric, on the other hand, went to
Odin's
hof and sacrificed for victory, promising himself to Odin after ten years. Later that night, a tall man wearing a hat low over his face appeared in his camp and gave Eric a reed; he told him to shoot it over the opposing army and to say
Óðinn á yðr alla ("May Odin have you all"). The next day, Eric obeyed Odin's command; the reed appeared to become a javelin as it flew over Styrbjörn's forces, who were all struck blind. Then an avalanche came down from the hillside and buried them all, killing all the Jomsvikings, including Styrbjörn. King Haraldr and the Danes fled back to their ships and sailed home; as they went they saw a spear flying overhead. The earlier
Odds saga munks praises
Sturbiornus and states that King Eric killed two-thirds of the large force arrayed against him and that people credited it to "great power of the devil", because he had promised himself to
Oddinus after ten years.
Hervarar saga ok Heiðreks (ch. 15),
Eyrbyggja saga (ch. 29) and
Knýtlinga saga (ch. 2), like Saxo's
Gesta Danorum (Book 10, ch. 2), mention Styrbjörn's defeat, but according to
Eyrbyggja saga, some Jomsvikings survived, retreating through the forest, and according to
Knýtlinga saga, King Haraldr and the Danes left before the battle after Styrbjörn burned his ships. None of these accounts mentions intervention by Odin.
Aftermath After the victory, King Eric mounted one of the
royal mounds and promised a great reward to whoever could compose a poem about the victory. Among his ranks was an
Icelandic skald named
Þórvaldr Hjaltason, who immediately composed a poem about the victory, for which the king rewarded him with a golden bracelet. ==Mentions on runestones==