The Last Ship
From Tolkien Gateway
The Last Ship was a poem of the lore of the Shire originating in the Fourth Age, and was probably derived from Gondor.
It spoke about a woman, Fíriel, who was so beautiful that the Elves offered to carry her over the Straight Road to Valinor, but she was unable to accompany them.
Other versions of the legendarium
The poem written by J.R.R. Tolkien and published in The Adventures of Tom Bombadil in 1962. It is a revised edition of the poem Firiel published in 1934.