born: 973 at Laugur in Hvammssveit in Iceland
died: 1060 at Helgafell in Snæfellsnes in Iceland
married: 1000 Bolli Þorleikson
Like many women in the Viking age, Guðrún was even harder than the men in her family, unwilling to allow a dishonor to stand unavenged.
Guðrún had been married and widowed twice when she met Kjartan at the hot spring baths in Sælingdalur. The two had warm affections for another from the start.
Kjartan had grown up with his beloved foster-brother Bolli, and the two did everything together. Kjartan bought a half-share of a ship in Iceland, and he and Bolli decided to sail for Norway that same year. Guðrún was not pleased with his decision to leave and would not agree to Kjartan's request that she wait for him for three years.
In Norway, Kjartan and other prominent Icelanders were held hostage by the king until they agreed to convert and be baptized. After a long resistance, the men were baptized. Yet the king would not let Kjartan and a few other hostages leave when he learned how poorly his missionary priest Þangbrandur had been treated in Iceland. Bolli left with some of the other Icelanders and returned home.
Back in Iceland, Bolli was not completely honest with Guðrún about Kjartan's fate. He asked her if she might consider marrying him, and she said she would not marry anyone else while Kjartan was still alive. Bolli replied that she might have to wait a long time. Eventually, a marriage was arranged between Bolli and Guðrún.
When Kjartan returned to Iceland, Guðrún realized Bolli's deception. The two foster brothers, once inseparable, became very cold. An escalating series of reprisals ended with Kjartan locking Bolli, Guðrún, and their household inside their house for three days, unable to get out to use their lavatory, which in the Viking age, was usually located in an out-building.
Guðrún incited Bolli and her brothers to attack and kill Kjartan as he traveled nearby with few companions. To avenge this death, Kjartan's brothers made plans to kill Bolli in return.
Bolli and Guðrún were at the sel of their farm, sleeping quarters and a dairy in the higher pastures where livestock were kept and milked in summer. Bolli had sent out the farmhands to their chores for the day, and he Guðrún were alone in the building when the brothers and their supporters rode up. Hearing them, he sent Guðrún away, out of the building while he prepared to defend himself from inside. Guðrún went to the nearby stream to wash her linen.
Bolli defended himself well against the onslaught, but eventually, Helgi ran him through with his spear. The saga describes the end of the fight.
Bolli was still leaning against the wall of the cabin, holding his cloak tightly to contain his entrails. Steinthor Olafsson rushed at him and struck him a blow on the neck above the shoulders with a great axe, severing his head cleanly.
Then they left the cabin.
Gudrun then left the stream and came up towards Halldor and his party, and asked for news of their encounter with Bolli. They told her what had happened. Gudrun was wearing a long tunic, a close-fitting woven bodice and a mantle on her head. She had bound a shawl about her that was decorated in black stitching with fringes at the end. Helgi Hardbeinsson walked over the Gudrun and used the end of her shawl to dry the blood of the spear with which he had pierced Bolii. Gudrun looked at him and merely smiled.
Halldor said to him, "That was a vile thing to do, and merciless of you."
Laxdæla saga, ch. 55
At the time, Guðrún was pregnant with Bolli's son. Guðrún raised the boy, and when he was 12 years old and grown enough to seek revenge, she again incited him and his brother in the same way she incited her husband years earlier. Together, with the assistance of older men, they attacked Helgi. Bolli struck the deathblow, using his father's sword, Leg-biter.
When she was older, Guðrún became very religious, and late in her life, she became the first nun in Iceland. She lived in sorrow with the memories of her deeds. Near the end of her life, her son Bolli asked her which of her four husbands she loved most. Her response was that she was worst to the one she loved the most, usually interpreted to mean Kjartan, although other interpretations have been put forward. Guðrún died at Helgafell, and her grave is adjacent to the church at Helgafell.