Elwing was the daughter of Dior Eluchíl and Nimloth of Doriath. She had two sons with her husband Eärendil - Elros and Elrond.

Her father inherited a Silmaril from Beren, and when Dior Eluchíl was killed by the sons of Fëanor, Elwing took the Silmaril and left with many others of her kin in search of the sea. More escapee elves from the fall of Gondolin came to join their clan. She eventually came to Sirion and there wed Eärendil.

There came a time when Eärendil wished to sail out to Valinor and tell the Valar of the Elves’ message. He sought out Círdan and built with him a boat called Vingilot. Elwing, however, stayed in Sirion. Eärendil left and sailed upon the sea, but did not find Valinor, and soon he returned to Sirion because of his longing for Elwing.

Meanwhile, Maedhros, son of Fëanor, found out that Elwing lived and still held the Silmaril, and so went out to find her. When he found her, Elwing would not surrender the Silmaril, and a great fight - the last of the Elven kinslayings - took place for possession of the jewel.

The other sons of Fëanor came and fought also, though at the end of the battle, only Maglor and Maedhros remained. The ships of Cirdan and Gil-galad came too late to aid them, and Eärendil came not at all. Elros and Elrond had been taken captive and Elwing threw herself into the sea, along with the Silmaril upon her breast.

Ulmo found Elwing and took her out of the sea and transformed her into a great sea bird. The Silmaril was left on her, so that she shone like a star everywhere she flew. So she flew to find Eärendil, and came upon him in his ship. It is said that when she saw him she fell upon the deck in exhaustion.

Eärendil picked her up and slept with her by his side, and when he awoke, he was surprised to find his wife in her human form next to him. They sought out Valinor once more, and with the Silmaril bound upon Eärendil’s brow they found the Undying Lands and he became the first Man to walk on those shores.

Eärendil then told Elwing that he alone would walk on those shores so to not anger the Valar. But Elwing came with him nonetheless, and Eärendil bade her stand on the shores until he came back, for it was his fate only to bear the message to the Valar.

Elwing waited long, but becoming bored, she wandered to Alqualondë and befriended the Teleri who had their ships docked there. There Eärendil found her when he returned.

But soon they were summoned to Valimar again. The gods told them that they could choose between immortal and mortal life. Elwing chose immortality because of Lúthien, and so Eärendil did also.

Then the Valar built a ship for Eärendil’s men to sail home in, and Eärendil sailed in Vingilot to the Door of Night, where he flew among the stars. Many could see his Silmaril shining among the stars at night.

Elwing did not like the cold void, so the Valar built her a tower by the sea in Eldamar. There she learned all of the languages of birds, for all seabirds lived with her. At the times when Eärendil sailed near Arda she flew out to meet him again.