[Footnote 76: This part of the Younger Edda corresponds to the Latin Ars Poetica, and contains the rules and laws of ancient poetry.]
Brage told Æger that Thor had gone eastward to crush trolls. Odin rode on his horse Sleipner to Jotunheim, and came to the giant whose name is Hrungner. Then asked Hrungner what man that was who with a golden helmet rode both through the air and over the sea, and added that he had a remarkably good horse. Odin said that he would wager his head that so good a horse could not be found in Jotunheim. Hrungner admitted that it was indeed an excellent horse, but he had one, called Goldfax, that could take much longer paces; and in his wrath he immediately sprang upon his horse and galloped after Odin, intending to pay him for his insolence. Odin rode so fast that he was a good distance ahead, but Hrungner had worked himself into such a giant rage that, before he was aware of it, he had come within the gates of Asgard. When he came to the hall door, the asas invited him to drink with them. He entered the hall and requested a drink. They then took the bowls that Thor was accustomed to drink from, and Hrungner emptied them all. When he became drunk, he gave the freest vent to his loud boastings. He said he was going to take Valhal and move it to Jotunheim, demolish Asgard and kill all the gods except Freyja and Sif, whom he was going to take home with him. When Freyja went forward to refill the bowls for him, he boasted that he was going to drink up all the ale of the asas. But when the asas grew weary of his arrogance, they named Thor's name. At once Thor was in the hall, swung his hammer in the air, and, being exceedingly wroth, asked who was to blame that dog-wise giants were permitted to drink there, who had given Hrungner permission to be in Valhal, and why Freyja should pour ale for him as she did in the feasts of the asas. Then answered Hrungner, looking with anything but friendly eyes at Thor, and said that Odin had invited him to drink, and that he was there under his protection. Thor replied that he should come to rue that invitation before he came out. Hrungner again answered that it would be but little credit to Asa-Thor to kill him, unarmed as he was. It would be a greater proof of his valor if he dared fight a duel with him at the boundaries of his territory, at Grjottungard. It was very foolish of me, he said, that I left my shield and my flint-stone at home; had I my weapons here, you and I would try a holmgang (duel on a rocky island); but as this is not the case, I declare you a coward if you kill me unarmed. Thor was by no means the man to refuse to fight a duel when he was challenged, an honor which never had been shown him before. Then Hrungner went his way, and hastened with all his might back to Jotunheim. His journey became famous among the giants, and the proposed meeting with Thor was much talked of. They regarded it very important who should gain the victory, and they feared the worst from Thor if Hrungner should be defeated, for he was the strongest among them. Thereupon the giants made at Grjottungard a man of clay, who was nine rasts tall and three rasts broad under the arms, but being unable to find a heart large enough to be suitable for him, they took the heart from a mare, but even this fluttered and trembled when Thor came. Hrungner had, as is well known, a heart of stone, sharp and three-sided; just as the rune has since been risted that is called Hrungner's heart. Even his head was of stone. His shield was of stone, and was broad and thick, and he was holding this shield before him as he stood at Grjottungard waiting for Thor. His weapon was a flint-stone, which he swung over his shoulders, and altogether he presented a most formidable aspect. On one side of him stood the giant of clay, who was named Mokkerkalfe. He was so exceedingly terrified, that it is said that he wet himself when he saw Thor. Thor proceeded to the duel, and Thjalfe was with him. Thjalfe ran forward to where Hrungner was standing, and said to him: You stand illy guarded, giant; you hold the shield before you, but Thor has seen you; he goes down into the earth and will attack you from below. Then Hrungner thrust the shield under his feet and stood on it, but the flint-stone he seized with both his hands. The next that he saw were flashes of lightning, and he heard loud crashings; and then he saw Thor in his asa-might advancing with impetuous speed, swinging his hammer and hurling it from afar at Hrungner. Hrungner seized the flint-stone with both his hands and threw it against the hammer. They met in the air, and the flint-stone broke.