Of the Sun and Moon and the Hiding of Valinor
After Melkor and Ungoliant fled to Middle-earth, the Valar sat long in thought, holding council without voices, in grief of both the loss of the Trees and the corruption of Fëanor. When Manwë’s herald told of Fëanor’s answer, he wept, and Mandos foresaw that Fëanor would soon die.
Yavanna and Nienna attempted to heal the Trees, but all that they yielded before the Trees died was a single silver flower from Telperion and a single golden fruit from Laurelin. These they gave to Aulë, and his people made vessels for them—the Sun (Anar) and the Moon (Isil)—and Varda gave them power to traverse the skies, wishing to light all of Arda to hinder the work of Melkor and for the sakes of the Elves of Middle-earth and the Men, who Manwë believed would be arriving soon.
Arien was chosen from among the Maiar to guide the Sun, for she had cared for Laurelin and had not feared Laurelin’s heat. She was a spirit of fire whom Melkor had not corrupted to his service. Tilion was chosen from among the Maiar to guide the Moon; he was a hunter of Oromë and he loved silver, and he begged to be the keeper of the last flower of Telperion. Arien was the more powerful of the two and as bright as a flame. Not even the Elves could look her in the eye.
Isil was the first of the vessels to be ready and—as Telperion had been the older of the Trees—was the first of the lights put into the sky. Many things which had been under the sleep of Yavanna awakened then, and the Elves were delighted. Fingolfin’s host first set foot into Middle-earth with the rising of Isil.
When Tilion had crossed the sky seven times with Isil, Anar was launched and brought full light to the world. Morgoth was frightened by this and hid deep in Angband, withdrawing his servants, and put forth smoke to hide his realm from the light of the Sun.
Varda’s original plan was to have the two vessels always aloft in the sky but on opposing paths, meeting above the middle of the earth once per day, in the fashion of the Mingling of the Lights. But Tilion did not hold his course and sought to come near Arien, although she scorched him, and the Moon was darkened. Because of Tilion’s waywardness and the protests of Estë and Lórien that sleep had been banished and the stars were hidden in the splendor of Anar’s light, Varda changed her counsel and allowed Anar to sink into the west and pass beneath Arda, allowing a restful time of half-light before Anar rose anew in the east. Isil was supposed to move in a like manner, but Tilion was inconsistent in his pace and was still drawn to Arien, and there are times when both vessels are in the sky or Isil blocks Anar and the light of day.
The light was still fairest in Valinor, for Anar rested there at the end of each day, but the light of Anar and Isil is not as pure as the light of the Trees, unspoiled by Ungoliant. That light exists only in the Silmarils. Morgoth hated both Isil and Anar and attempted to assail Tilion, but he was not successful. Having put his power into evil creatures, Melkor’s power had become dispersed across and firmly bound to the earth, and he no longer had the power to assail Arien or even bear her glance for long. He put out clouds over his land to hide from her light.
The Valar grew fearful with the attack on Tilion, however, and they strengthened the mountains that guarded their lands and increased their vigilance and set also the Enchanted Isles, a dangerous network of islands shrouded in mist and weariness, in the sea before Tol Eressëa. Anyone who set foot on these islands fell into interminable slumber, and it was as Mandos had foretold: Aman was shut against the exiled Noldor.