The appointed moment had come for the Elder Children of Ilúvatar to awaken at the shores of Cuiviénen. The Valar held Council and decided to wage war on Melkor. There went Eönwë the herald bearing the sapphire-blue banner of Manwë. Among the army marched also Tinwen, Élanga in her belt, and in battle she slew one who had been her brother, a spirit of fire who served Melkor, a valarauka. The victory of the west was swift; they drove Melkor into Utumno and besieged the fortress. Finally the gates were broken and Tulkas wrestled Melkor and he was taken captive. But Sauron they did not find, and Tinwen was troubled.
The victorious army returned to Aman, and Melkor was put under judgement by Mandos. Thus began the Summer of Arda. And it came to pass that the Eldar finally arrived to Aman. Such joy there was in the land those days, when the Vanyar, the Noldor and the Teleri beheld the light of Laurelin and Telperion. And none was more pleased at the sight of the Children of Ilúvatar than Tinwen Híniel, who clothed herself in the shape of an elf-child and played with the children of the newcomers. She taught them all her games and songs, and there were many of these. Thus time passed.
Then one was born to shine like a golden star: Alatáriel, daughter of Finarfin. This little one became dearer than any other to Tinwen. Hand in hand they walked under the trees of Kementári, side by side they sat under the stars of Elentári, heart to heart they understood each other, soul to soul they belonged together. When they slept in Lórien they shared their dreams, and often they dreamed of a great light rising in the East, red and golden.
When Alatáriel grew to be a maiden, Tinwen changed her raiment also. She turned her hair golden like her friend's, and they resembled each other so much that many elves confused one for the other.
When Eönwë saw Tinwen in a maiden's shape, he fell in love and asked her to marry him. Tinwen replied she would like to see her friend Alatáriel married first. However, they were engaged and Eönwë gave Tinwen a diamond ring crafted by Aulë.
The Summer of Arda was long, but eventually the fruits of talent had all ripened, the flowers of youth had bloomed, the birds of joy were preparing to fly away and the skies of hope were turning grey. Feänor had made the Silmarils. Melkor was unchained.
Tinwen hated the Dark Lord who had led Turon away from her. The sad memories within her stirred when she saw her enemy walking free. More and more she yearned for the Spring to return. She preferred to be alone more often, though she tried to tell Alatáriel about her worries. Tinwen started to think that perhaps Melkor had indeed changed, and then she wondered whether Thauron could change too. Whether Tinwen herself could change him. She went to talk with Melkor. She did not know then, but it was Melkor's idea and not hers that she should seek Thauron. She learned the place where he ought to be found - in Middle-Earth, under Angamando (the fortress known in lore by the Sindarin name of Angband).
Tinwen remembered full well she had promised not to run away. Therefore, she asked Eönwë to take her up the Taniquetil. There she was allowed an audience with Manwë and Varda.
'High Lord, I have come to ask permission to depart from Aman.'
'You may go,' said Manwë, 'and my blessing goes with you.'
But the eyes of Varda held worry, and Eönwë tried to hide his shock. On the way back down he asked Tinwen many questions. Tinwen's only response was returning him his ring.
Alatáriel was grieved, but could not alter her friend's decision. Tinwen tried to comfort her.
'My beloved one, I know we will meet again. I shall not bid you farewell. Nor shall I give you any gift of departure. I shall give you a new name, and give you also me a name. You are Lauremiriel.'
'My sister, you are El-Carnil.' And they laughed, and embraced. They parted, and they wept.
Lauremiriel = golden jewel
El-Carnil = the star Carnil (a red star)