Now the witch, the mother of Gudrun, wanted her son Gunnar to marry Brynhild, and she bade him ride out with Sigurd and go and woo her.So forth they rode to her father's house, for Brynhild had quite gone out of Sigurd's mind by reason of the witch's wine, but she remembered him and loved him still.Then Brynhild's father told Gunnar that she would marry none but him who could ride the flame in front of her enchanted tower, and thither they rode, and Gunnar set his horse at the flame, but he would not face it.
Then Gunnar tried Sigurd's horse Grani, but he would not move with Gunnar on his back.Then Gunnar remembered witchcraft that his mother had taught him, and by his magic he made Sigurd look exactly like himself, and he looked exactly like Gunnar.Then Sigurd, in the shape of Gunnar and in his mail, mounted on Grani, and Grani leaped the fence of fire, and Sigurd went in and found Brynhild, but he did not remember her yet, because of the forgetful medicine in the cup of the witch's wine.
Now Brynhild had no help but to promise she would be his wife, the wife of Gunnar as she supposed, for Sigurd wore Gunnar's shape, and she had sworn to wed whoever should ride the flames.And he gave her a ring, and she gave him back the ring he had given her before in his own shape as Sigurd, and it was the last ring of that poor dwarf Andvari.Then he rode out again, and he and Gunnar changed shapes, and each was himself again, and they went home to the witch Queen's, and Sigurd gave the dwarf's ring to his wife, Gudrun.And Brynhild went to her father, and said that a King had come called Gunnar, and had ridden the fire, and she must marry him.`Yet I thought,' she said, `that no man could have done this deed but Sigurd, Fafnir's bane, who was my true love.But he has forgotten me, and my promise I must keep.'
So Gunnar and Brynhild were married, though it was not Gunnar but Sigurd in Gunnar's shape, that had ridden the fire.