The first sources of light for all of Arda were two enormous Lamps: Illuin, the silver one to the north and Ormal, the golden one to the south. These were cast down and destroyed by Melkor. Afterward, the Valar went to Valinor, and Yavanna sang into existence the Two Trees, silver Telperion and golden Laurelin shedding light comparable to moon and sun. Telperion was referred to as male and Laurelin female. The Trees sat on the hill Ezellohar located outside Valimar. They grew in the presence of all of the Valar, watered by the tears of Nienna.
Each tree was a source of light: Telperion's silver and Laurelin's gold. Telperion had dark leaves (silver on one side) and his silvery dew was collected as a source of water and of light. Laurelin had pale green leaves trimmed with gold, and her dew was likewise collected by Varda.
One "day" lasted twelve hours. Each Tree, in turn, would give off light for seven hours (waxing to full brightness and then slowly waning again), so that at one hour each of "dawn" and "dusk" soft gold and silver light would be given off together.
Jealous Melkor, later named Morgoth by Fëanor, enlisted the help of the giant spider-creature Ungoliant (the first great spider, ancestor of Shelob, and possibly a fallen Maia) to destroy the Two Trees. Concealed in a cloud of darkness, Melkor struck each Tree and the insatiable Ungoliant devoured whatever life and light remained in them.
Again Yavanna sang and Nienna wept, but they succeeded only in reviving Telperion's last flower (to become the Moon) and Laurelin's last fruit (to become the Sun). These were assigned to lesser spirits, male Tilion and female Arien, after the 'genders' of the Trees themselves. This is why, in The Lord of the Rings, the Sun is usually referred to as "she" and the moon as "he".
But a thousand years hence Ezellohar has eroded and the scars of its past have long weathered away. Deep did the roots of the Two Trees delve, deeper than fell Morgoth knew and deeper than Yavanna's song could resonate and deeper yet than Nienna's tears were known to descend into that hill's furtile soil.
And so it was that the Gardener, Marie Ravencrow, lover of trees and all that grows in the forests, in her roamings, came upon two saplings on that long forgotten mound in Valinor, beyond the bounds of Valimar, and without knowledge of their beginnings in that far forgotten age, took them with care and love to her gardens and nurtured them into youthful vigour.
Then at last came a wanderer, a traveller from the land of Elvenholde, an Elfen, a lover of trees and forests, and springs and waterfalls, and of birds and creatures of the woods, and espying the gardens of the Good Lady Ravencrow did delight in all he saw about him and of the Gardener's works and was mightily pleased with all that he had found. But when at last he believed that his delight could be no greater, he stood before two newly matured trees and was struck with wonder, for all that he once feared lost in the depths of time stood tall and proud before him as descendants of the Two Trees, Telperion and Laurelin.
To the Lady Marie did the Elfen wanderer speak and of the Two Trees and of their beginnings and of their meaning, and in time did the good lady grant that the Two should be planted anew in Elvenholde in the care of the Forrestal, in the care of Bryster Shan. And there stand the two, one to light the day, one to light the Eve at the resting of the sun in the sky, that there might be no hope lost as lost it became on the withering of the Ancestors on a hill called Ezellohar.
(From A History of The Elf Clan - The Yet To Be Written)