In the early days the moon did not shine as brightly as it does now, the moon god Mane had to come down to the earth to draw up some water from the underworld to give the moon its silver glow.
Even as far back as the time just after the creation the gods feared that the seas to the north of Middle-earth would freeze over, and an ice age set in. The strife that the cold would bring, would according to their prophecies precede the Ragnarok, the fateful day when the world descends back into the chaos that it originally derived from.
After Dvalin the second greatest of the dark elves was Ivaldi, he first had four sons with two giant wives; Thjassi, Idi, Urner and Hjuke, and a daughter Bil. The mothers of Ivaldi's first family are Fenia and Menia two of the giantesses who push the handle of the world mill on the edge of creation.
Odin sought Ivaldi in his hall of stone in the underworld and asked him for his assistance. You are the greatest of the elves, we need you to stand guard at the north to watch that the sea does not harden into solid ice.
Ivaldi desired recognition of his worth from the gods and announced that he would take up the post: The sea will never harden while I stand guard over the north.
Ivaldi left the underworld with his son Hjuke and his daughter Bil. Before Ivaldi left he told his favorite son, the great craftsman and fighter Thiassi: Stay working at the Ivaldi furnace because the gods will soon come down to the underworld to ask you to forge treasures for the worlds above.
Under the guardianship of the Ivaldis the seas to the north of Middle-earth remained ice free and Ivaldi became the folk hero of the Swedes and Finns who called him Vidfinnr or Finnrkongr. The Saxons name him Fin Folcwalding. The gods gave Ivaldi the hand of the sun goddess Sol in marriage for they feared that his task would engender a frostiness in his heart and a coldness in his mind but those fears were allayed when Sol had a daughter Idunn the goddess of orchards, every autumn she collects the apples that rejuvenate the gods and keep the world from growing old and withering.
The gods recognized Ivaldi's greatest strength, but this was also to prove to be his undoing. Ivaldi always desired great tasks and great knowledge, Ivaldi knew that Odin had drank of the clear water of inspiration from the well of Mimer in the underworld before he created Middle-earth, but Ivaldi could not make the sacrifice Odin had to gain the drink: he could not hang on the Yggdrasil and die and return like Odin and he was not going to leave one of his eyes in Mimer's well of inspired thought even if he would be able to see everything with the other one.
As Ivaldi guarded the northern waters he watched his wife Sol cross the sky every day, her horses pulled the suns blazing chariot but he felt little of the heat from the molten orb her horses drew. He looked out over cold seas and the stars on his brow, forged by his own will penetrated the ice and broke up the floes before they hardened.
One day Sol crossed the heavens and saw a pool below her in Middle-earth, it was shining so brightly that she told her husband of its whereabouts. The existence of this pool made Ivaldi think that he could rival Odin because he knew where the water originally derived from. There had been an upsurge in the underworld: an overflow of the subterranean waters flowing from Mimer's well. The overflow had formed into a stream which sprung upwards and out of the underworld into Middle-earth, and then into a pool called Byrgir, and only he Ivaldi knew the water came from a well in the underworld: Mimer's, and he kept this secret to himself. When I have drunk the clear mead of inspiration from the pool Byrgir I will be able to rival Odin in thought.
In the early days the moons orb appeared dulled, as if it was permanently entering into a eclipse or obscured by clouds. Sols brother Mane the moon god, the captain of the lunar orbs sky voyage, also saw the pool Byrgir at the same time as Ivaldi: The shining pool in Middle-earth is like no other body of water I have ever seen beneath me because it reflects back the moonlight a thousand times, I need that water to light up the lunar disc to illuminate the thoughts of Middle-earth's folk during the dark hours. Mane tried to steer the moon ship down to take up some of the water from Byrgir but he never succeeded because he was always obstructed by trees that had sprung up near the waters edge.
But Ivaldi was also determined to take the water from the pool and drink it. Fearing that some disaster might befall if he left his post at the north of the world Ivaldi gave his children instructions as to where the pool lay and said: Take these two buckets and fill them to the brim with the water and bring them back to me.
They found the pool in the dark and filled the pails then set of back to their father just as the moon was starting to rise in the dark sky. The moon god Mane saw them and his light guided them back through the trees. Then Mane saw how brightly the water in the buckets was glistening , and how much Bil and Hjuke had taken from the pool, he then swept down and took the buckets and their bearers up with him into the sky.
When Ivaldi saw Bil and Hjuke rising into the sky with the moon god black wings of anger sprang from his shoulders and he left his post by the cold seas of the north. Raging heavenwards he made an assault on the moon, but he failed, falling short of the sky. If his flight had succeeded the glistening drink would have been his, but in taking it violently from Mane he would have ended the moons orbit. Manes ship sails higher than any elf can fly and Bill and Hjuke and the two buckets of water from the pool Byrgir rose with the moon god into the celestial region above the world. When Bil and Hjuke drank the water from the underworld the moons disc was struck through with silver light.
After the Moon god escaped from him Ivaldi considered that he had been sorely wronged because he felt that the drink that should have been his, along with two of his children, had been taken by the moon god Mane. He went to the counsel of the gods in Asgard to demand that they make the moon god return his son and daughter and the buckets containing the water from the pool called Byrgir: Everything I have and everything that I have ever valued has been stolen from me by Mane, if you can make the moon god return Bil and Hjuke and their buckets to me only then we will be able to return to the north and crack the ice floes for Middle-earth. This was Ivaldi's demand.
Odin's judgement on the dispute between the elf and the moon god was rendered thus: You are Bil and Hjuke's father, Mane has only taken as much of the water from the pool as you would have kept for yourself. If your assault on the moon god had succeeded you would have won the drink, but we would have lost the moon. As soon as Bil and Hjuke ascended into the sky with the overflow from the well in the underworld we saw the moon shine as it never did before, it was your lack of wisdom that made you tell Bil and Hjuke to take so much of the water in their pails that the moon god saw it overflowing, flashing in the dark, far brighter than the moons disc.
Tyr the lawmaker decreed: Mane then saw that Bil and Hjuki and the water from the underworld should be with him. So the water shall stay with the moon forever and shine over the world.
What Odin said was true, Bil and Hjuke drink the water from the underworld and their shadows wax and wane across the lunar orb every month. Odin visits Bil just as the moonship sinks towards the horizon in the west and refreshes himself with her drink.
Un obscured by clouds the moons light is a great gift from the underworld because it guides your path in the dark and can give rise to inspired thoughts.
After the gods judgement went against him Ivaldi became estranged from his wife the sun goddess, he then fled his post by the northern seas. Now that Sol was gone he feared the cold but most of all he sought the drink he considered to have been wrongly taken from him.