Brunhild is introduced to the story when word of her immense beauty reaches Worms one day, and King Gunther decides he wishes to marry her. Siegfried, who is familiar with Brunhild, advises him against this marriage, but Gunther convinces Siegfried to help him woo Brunhild by promising to let Siegfried marry Gunther's sister Kriemhild. Gunther needs Siegfried's help because Brunhild has set a series of three feats of strength that any suitor for her hand must complete; should the suitor fail any one of these feats, she will kill him. Siegfried agrees to help Gunther by using his cloak of invisibility ("Tarnkappe") to aid Gunther during the challenges, while Gunther will simply pretend to accomplish them himself. He and Gunther agree that Siegfried will claim to be Gunther's vassal during the wooing.