Jormunrek (also spelled Jormunrekk or Iormunrekk), in Norse mythology, a mighty king who murdered the lovely Swanhild and was himself slain by her stepbrothers. The story is based on the historical figure Ermanarich, a 4th-century king of the Ostrogoths in what is now Ukraine. The story of how he heartlessly killed his own son and Swanhild (Svanhild), the beautiful daughter of the hero Sigurd and Gudrun, is told in the 'Poetic (or Elder) Edda', the 'Prose (or Younger) Edda', and the 'Volsunga Saga'.
Swanhild had been brought up in Denmark after her mother married King Jonakr. King Jormunrek the Great heard of Swanhild's great beauty and wanted to marry her. He sent his son Randver to Denmark on his behalf to ask for her hand and entrusted him to bring the young woman to him. Bikki, counselor to the king, accompanied Randver, and encouraged him to consider marrying Swanhild himself rather than give her to his elderly father. Randver and Swanhild agreed. Bikki then betrayed Randver by telling the king that his son and Swanhild were in love. Jormunrek had his son arrested and taken to the gallows. Just before he was hanged, Randver plucked the feathers from his hawk and asked that the bird be sent to his father. When King Jormunrek saw the naked hawk, he realized that just as the hawk was now unable to fly, he had dishonored his own kingdom by condemning his only heir. He called off the hanging, but it was too late.
King Jormunrek blamed the innocent Swanhild for his misfortunes. In one version, he rode in from the forest after hunting with his men, and as Swanhild was sitting bleaching her hair, had them ride over her, trampling her to death. In another version, she was bound to the castle gate. The king's men were instructed to drive their horses over her, but when she looked at the horses, they would not tread on her. The treacherous Bikki had a sack put over Swanhild's head, and she subsequently died under the horses' hooves.
When Gudrun learned of this, she incited her sons, Hamdir (Hamthir), Sorli, and Erp, to vengeance. She told them to attack the old king in his sleep, and she gave them chain mail and helmets so strong that iron could not pierce them. They came up with a plan whereby Hamdir and Sorli were to cut off Jormunrek's arms and legs, while Erp would cut off his head. The three brothers got in a fight on the way, however, and Hamdir (Hamthir) and Sorli killed Erp. As the two surviving brothers attacked the king and cut off his arms and legs, the king woke up and was able to call out to his men. They realized that if they had not killed Erp, the king would have died before he could alert the guards to their deed. Jormunrek's men, on the king's last command, stoned Hamdir and Sorli to death.