During this time Brunhild was always in his memory, and he talked so often of her that at length the evil heart of Grimhild, the queen, was roused to jealousy. She bethought herself that, could he but be made to forget the maiden of the Flaming Castle, he might marry Gudrun, her daughter; and so all the wealth of Andvari's hoard might remain in the court of the Niblungs for ever. On a day, therefore, she mixed a magic potion, and gave it to Sigurd, saying: "We have great joy in thy visit here, and would give thee the best that we enjoy. Now take this horn, and drink therefrom." So he drank with gladness; and from that moment all remembrance of Brunhild was blotted from his mind, as though she had never been. And, as the queen had hoped, he began to look with eyes of affection upon Gudrun, the fair maiden whom he saw every day, so that the Niblung princes, who had grown to love and honour Sigurd more and more, came to him and said: "Great good thou hast brought us, Sigurd, and exceeding strength thou givest to our realm. We pray thee therefore to abide with us for ever, and thou shalt have rule in our land, and we will give thee our sister in marriage, whom another man would not get for all his prayers." Then the heart of the Volsung responded, and they swore brotherhood together, even as if they were children of one father and mother; and in due time Gudrun was married to Sigurd with all joy and festivity. Yet, in the midst of all this glee, a strange feeling oppressed the heart of Sigurd. Some old memory seemed to be striving within him, but, try as he would, he could not give it definite shape. Time passed and King Giuki died, Gunnar, his son, succeeding him. And as he had no wife, his mother, Grimhild, said: "Fair is thy life and fortune, O my son, but one thing thou lackest. Go, seek for thyself a wife who shall be a joy to thy house." "But where can I find one who will be a worthy queen of the Niblungs?" asked Gunnar. And his mother answered: "Fair among the daughters of the earth and bravest of warrior-maidens is Brunhild. In her Castle of Flames she awaits the bridegroom who shall dare to penetrate the barrier of fire. Go then, seek her out, and Sigurd will ride with thee." So Gunnar and Sigurd arrayed themselves joyously and rode away, till on the crest of a high mountain they saw a castle with a golden roof and all about it a ring of flaming fire. Then right eagerly they pricked their steeds, but all too long it seemed ere they gained the summit. At length they reached the fiery wall, and Gunnar put his tired horse at it without pause. But the horse trembled and stood stock still. Again and again he tried him, but always with the same result, until, at length, Gunnar cried to Sigurd: "Lend me thy steed, Sigurd, for mine will not brave this fire." "With all my heart," replied Sigurd, leaping off Greyfell. But when Gunnar had mounted the horse, Greyfell would not stir, and he too trembled before the flames.