In after days, when because of the triumph of Morgoth Elves and
Men became estranged, as he most wished, those of the Elven-race
that lived still in Middle-earth waned and faded, and Men usurped
the sunlight. Then the Quendi wandered in the lonely places of the
great lands and the isles, and took to the moonlight and the
starlight, and to the woods and the caves, becoming as shadows
and memories, save those who ever and anon set sail into the West
and vanished from Middle-earth. But in the dawn of years Elves
and Men were allies and held themselves akin, and there were some
among Men that learned the wisdom of the Eldar, and became great
and valiant among the captains of the Noldor. And in the glory
and beauty of the Elves, and in their fate, full share had the
offspring of elf and mortal, Earendil, and Elwing, and Elrond
their child.
[ The Silmarillion, by J.R.R. Tolkien ]