§ Of the Voyage of Eärendil and the War of Wrath The Silmarillion

Thus Maedhros and Maglor gained not the jewel; but it was not lost. For Ulmo bore up Elwing out of the waves, and he gave her the likeness of a great white bird, and upon her breast there shone as a star the Silmaril, as she flew over the water to seek Eärendil her beloved. On a time of night Eärendil at the helm of his ship saw her come towards him, as a white cloud exceeding swift beneath the moon, as a star over the sea moving in strange course, a pale flame on wings of storm. And it is sung that she fell from the air upon the timbers of Vingilot, in a swoon, nigh unto death for the urgency of her speed, and Eärendil took her to his bosom; but in the morning with marvelling eyes he beheld his wife in her own form beside him with her hair upon his face, and she slept.