Loki, Thor's father's brother was never content with his faithful wife Sigyn and was jealous of Thor from the first day that Thor met the Vanagoddess. He knew how much Thor admired Sif's golden hair and when they were married in the summer Loki heard thunder split the rain clouds to water and ripen the corn. So Loki contrived to play a malicious trick on Sif. One night when Thor was away he crept into her room as she slept and cut of all her hair, and as he left he threw it all over Thrudheim .
When Sif awoke the next morning she was filled with grief: her hair was gone, and when Thor returned to Asgard that day after defending Middle-earth from the giants, seeing his wife's golden locks strewn around Asgard, he was filled with rage because the sight of Sif's remaining hair reminded him of what he constantly fought against: her shorn head resembled a field of patchy stubble blighted by a cruel frost. Thor immediately knew who had done the deed:
Only Loki can slip undetected into the rooms of the goddesses as they sleep, and only Loki would find amusement in such a malicious act.
Thor soon found the trickster and told him that under the pain of death he should restore Sif's hair and make it grow like it did before: he told Loki where Sif's hair could be renewed: Go to the dark elves and get them to spin hair for Sif that can grow on her head, shine and move with life in the summer just like it did before you cut it off last night.
Loki descended into the land of the dark elves in the underworld and found the rocky halls of the dark elves, he went from forge to forge, listening at the gates, all the time remaining unseen watching Dvalins's apprentices at work forging casting and shaping, all the time he listened for stories and rumor: Loki wanted to know who were the greatest of the underworlds artists, and out of all the stories he heard the names that were the most prominent in the tales were the Ivaldi sons and Brokk and Sindre.
Now that he knew where to find what he sought Loki soon found the great Ivaldi furnace blazing in the dark. Thiassi, Idi and Urner were smelting lodestones they had delved from the earth's deepest veins in their crucibles, transforming the ores into wonders for the worlds above them. Loki walked into their forge and announced to the sons of Ivaldi the misfortune that had befallen Sif while neglecting to mention who was responsible for her plight: Sif's golden hair has been ruined, shorn in the night and cast on to the floor. Sif is still crying and Thor is angered, Asgard asks for just one favor from the sons of Ivaldi: that you remake Sif's hair and use your magic to make it grow on her head just like it did before last night.
Thiassi replied to Loki's request: To restore Sif's hair and make it grow and move as if it lived just like the corn harvest did would be a regular task for us.
Loki promised Thiassi: The Aesir will repay you well if you can do this: you will earn the eternal friendship of the gods and Thor's protection .
Then the sons of Ivaldi applied their powers: Idi blew the bellows so hard that smoke filled the underworld. The earths metallic blood held fast in the lodestones ran free from the rock to be transformed and cast according to the will of the dark elves. Thiassi hammered the gold into long threads singing over them as they grew on the anvil, then he took the strands one by one and handed them to Loki.
Thiassi said: Is this not just like Sif's hair?.
Loki was amazed by the life and movement in the gold strands and told Thiassi: The worlds above will marvel at your craftsmanship.
The dark elves returned the corn harvest to the world.
The furnace was hot and the metals in the crucibles were still molten and waiting to be formed: Rather than waste the blaze from the furnace we can create some more treasures for the gods and the worlds above Thiassi told his brothers.
So Idi blew the bellows again and said: We will make a ship for Frey, its sails will sing so well with the wind that the roughest billows or lightest breeze will take the sailors in it to where the fishes swim.
Thiassi made the ship with such skill that Loki again was amazed by the artistry of the sons of Ivaldi. Thiassi showed Loki what the ship could do: When the ship is taken onto land it can be dismantled and folded up into such a small size that you can carry it around in your pocket, this boat is called Skidbladner and is a gift for the god Frey.
The dark elves gave the world a ship to fish the ocean with.
Thiassi saw how hot the Ivaldi furnace had become and said : We can now make a spear for Odin.
He told his brothers to find the hardest ores and set them free from the stone in the hallowed furnace. At the Anvil Thiassi hammered the iron into the spear Gungner. When the spearhead had cooled Thjasse handed it to Loki and said: This spear is for Odin, it will never miss its target and will stop all of Odin's foes dead in their tracks. Take all these treasures to Asgard and remind the Aesir of the favors we have done for them and the gratitude the world above owes us.
Loki thanked the sons of Ivaldi and left their hall with the gifts. But when he stood outside their rocky gate he paused and thought: I can get even more from the dark elves than I have already talked them into giving me.
So the father of lies next sought the forge of Brokk and Sindre. Upon arrival he openly displayed the golden hair that Thiassi had imbued with life and the spear Gungner, the deconstructable ship Skidbladner was folded up in his bag. On seeing such finely crafted works Brokk and Sindre felt a certain envy towards the creators of the treasures, and envy was what Loki wanted to work into their minds. Brokk and Sindre were immediately suspicious of Loki's intentions even as their curiosity was ignited by the sight of the sons of Ivaldis treasures.
Loki struck up a wager with the elves: I will stake my head that there is no one in the underworld who can make better works than these.
Brokk replied: Loki if you stake your head on this wager we will win because all our skill will be put into the work so that when it is done the world will be rid of your scheming.
Brokk and Sindre left Loki in the hallway of their dwelling and went into the inner chamber where their forge lay. Brokk piled wood into the furnace and as he worked he sang, low at first under his breath, then louder as he blew on his fingers and rubbed his hands. Whispering , blowing and rubbing he made a spell come together that set the furnace ablaze. Sindre then put a pig hide into the forge and they began their work Brokk took up the bellows and started pumping hard, after a short while Sindre told him: Keep blowing as hard as you are now until the boar has been made.
Sindre took the gold from the fire and hammered out bristles on his anvil and then stuck them all over the hide. As the boar was taking shape Sindre left the smithy to get more wood and water, as he left he bade Brokk to keep pumping hard to heat the pigs hide further. But when Sindre was out of the chamber a fly buzzed in and settled on Brokk's arm and nibbled his skin while he was working the bellows, but he was so set on his task that he hardly noticed.
Sindre returned with the pales and wood and the work continued. When Sindre had finished forging a living boar walked out from the furnace, its golden bristles glowed and it stood in the underworld shining with its own light. Brokk and Sindre named him Gullinbursti and declared that he was a gift good enough for the harvest god Frey.
Sindre took another hot ingot of gold from the furnace and began to hammer it on the anvil, again he had to leave the forge for a moment and told his brother to keep pumping the bellows in his absence. Again as soon as he left the chamber the fly returned to distract Brokk. It landed on his neck and bit him harder than before, but again he was so engrossed in his task that he did not pause for a moment. When Sindre returned the fly disappeared and soon Sindre's work was completed: an arm ring had been crafted possessed of such powers that it can reproduce itself every nine nights by dripping eight rings of the same size and weight. Sindre named it Draupner and declared that it was a gift good enough for Odin himself.
Then Sindre took the hardest ores that the dark elves had ever mined, he told his brother: I am going to make a hammer so hard that the gods will be able to defend all the worlds with it.
As he was shaping it on the anvil he said to Brokk: Keep on pumping while I fetch some more water and fuel, do not stop for one moment or else the hammer will be ruined.
Again while Sindre was away the same malicious fly buzzed into the smithy and this time it settled between Brokk's eyes obscuring his vision and making him blink. Then Loki -for the fly was none other than the sly shapeshifter himself. started to bite at the elf's eyelids and blood dripped into his eyes blinding Brokk, for one moment he stopped pumping to brush the fly away as fast as he could. Then Sindre returned to the forge and the fly disappeared.
Brokks sight cleared and he watched Sindre take Mjollnir: the hammer of the underworld from the flames. Upon completion Sindre examined the hammer and said to his brother: So nearly ruined, this great hammer forged with my magic, it is a little too short in the handle but when you go to Asgard with Loki and tell the gods the qualities of the gifts that we have made, and how the hammer will be able to slay the frost giants when they threaten Asgard and Middle-earth, then you will win Loki's contest, and his head.
Brokk went with Loki to Asgard to witness the gods decision . When they arrived at heavens watchtower above the Bifrost rainbow bridge Heimdall greeted Brokk with courtesy but watched Loki with a suspicious eye.
Loki called for a council of the Aesir and Vanir to be held in Asgard and when the gods were assembled he announced: I have been to the underworld, there the sons of Ivaldi made hair from gold that will now grow on Sif's head just like it did before it was cut of, they also made two other great treasures. But when Brokk and Sindre saw what the sons of Ivaldi had made they were so jealous that they tried to rival them and forged works of their own. Odin, Thor and Frey must sit in judgement and decide who are the greatest smiths: the Ivaldi sons or Brokk and Sindre.
My brothers works will speak for themselves, Sindre said to the gods, to Loki he said: Then you will have no head to speak from because you will have lost the wager.
Loki placed the first of Thiassi's gifts to the gods upon Sif's head and it immediately rooted and shone with life, all the gods declared that her new hair looked even finer than it did before it was shorn , Loki told Sif: I said that I would restore your hair and I have done so.
Sif was happy again and Thor was pacified. Loki then displayed the Ivaldis other gifts: This spear is named Gungner, it is for you Odin, it never misses its mark.
Odin said that Gunger was a fine well balanced weapon and nobody disagreed. Loki then presented the small package to Frey: See here this is a ship, and to the wonder of all the gods he unfolded it and raised its sails: All the gods can sail in the ship Skidbladner when it is unfolded, when it is not in use it can be carried on land in your pocket. He then folded it up again.
Odin, Thor and Frey were pleased with the gifts that the sons of Ivaldi had made for them. Then Brokk presented to the gods the gifts that his brother and himself made to win Loki's wager: This is a gold ring for you Odin, it is called Draupner because every nine nights it drops eight rings of the same size and weight as itself so that its wealth spreads.
Odin was as pleased with the ring as he was with the spear from the sons of Ivaldi. Brokk then turned to Frey and the golden boar Gullinbursti trotted over to the harvest god. The shining boar Gullinbursti is for you Frey, he can charge all over the sea and air and wherever he runs, either through the densest forest or into the cold gloom of Niflheim he will always shine because we made bristles for Gullinbursti that spit and burn brightly.
Frey thanked the dark elf and said to him: This boar is a great gift to receive because he can light my way and pull my chariot.
Brokk then turned to Thor and presented the hammer of the underworld to the Thunderer. I have crafted this hammer Mjollnir to give you victory every time it is slung against the frost giants, when you use it all your strength will strike through it and it never misses its target when it is thrown, then it will fly back to your hand. When you are not using it we have given it such magic that it can become as small as you want so that you can carry it in your tunic. Brokk then added: There is one small fault in my work though, the handle is a bit short.
Thor examined the hammer and told Brokk: The handle seems good enough to me. But Thor would later need a bit more length in his hammer because it would fall short of its target when he was to confront his greatest enemy.
So Odin, Thor and Frey had to decide on whether Brokk and Sindre or the sons of Ivaldi had crafted the greater works. They decided that the greatest treasure of all was the hammer because it brought protection to the world and thunder and doom to the giants.
Odin said to Brokk: You have won Loki's contest.
Brokk replied: So now I can have my prize; Loki's head.
Loki thought that he could bribe the elf: I will give you as much gold as you and your brother can carry back down to the underworld.
Brokk was not to be pacified easily: We have plenty of gold in the underworld. Then he drew his knife and went for Loki's throat.
But Loki was wearing his sky shoes that enabled him to run through the air and before Brokk could catch him he was away on the wind. Brokk shouted to Thor to aid him, Thor wanting to see justice done because of the favours the elves had done for the gods in making such incomparable gifts set of after Loki and brought him back to meet his fate. Brokk had his blade at the ready to cut of Loki's head but the sly one had found a way to wrangle out of being beheaded: You have a claim on my head but not on any part of my neck.
The gods agreed that this was so.
Well then my claim on your head includes your mouth and now I am going to sew it up to stop the lies that issue from it. Brokk replied. The gods agreed that this was just.
Brokk produced a thong from his bag and with his knife he attempted to pierce the sly shapeshifters lips but the tip of his blade was not sharp enough for Loki's mouth. Brokk then called out to his brother Sindre to come from the underworld to help him. Sindre heard his brother call out to him and immediately appeared in Asgard with his awl. Sindre grabbed Loki and pierced his lips with the awl, then Brokk sewed them together and cut the ends of the leather off. When he had taken his revenge he completed his work with the neatness that is typical of the dark elves craft.
Loki fled from Asgard. As he ran he tore the bloodied thread of humiliation from his ragged lips and vowed to wreak vengeance on the gods and the elves and bring chaos back into the world. He set off to find Angrboda; the greatest of the giantesses in her settlement in the Ironwood and when he found her he stayed a long while away from Asgard, the offspring from their union would one day be the bane of all that Odin had created.
But when the sons of Ivaldi heard the news that the judgment of the gods favoured the works of Brokk and Sindre over their own crafts Loki's spell of envy was cast deep into the minds of the dark elves and they regarded it as a mortal insult, born of the ingratitude of the gods and the sons of Ivaldi never worked again for the world above.
Idi and Urner sat without motion or action in their hall of stone below Middle-earth, their art was stilled and the great Ivaldi furnace lay cold. Thiassi the greatest of Ivaldis sons left his brothers to take up a new abode - in a mountain above the land of the giants. Sitting in his eyrie above the world Thiassi shape shifted in his rage and took on eagle form. The former friend of the gods then became their most irreconcilable enemy. The promoter of growth and benefactor of nature allied himself with the giants of frost and chaos and changed into the mightiest foe of the world; Thiassi assumed the nature of a storm giant.