Yet at the last Beren was slain by the Wolf that came from the gates of Angband, and he died in the arms of Tinúviel. But she chose mortality, and to die from the world, so that she might follow him; and it is sung that they met again beyond the Sundering Seas, and after a brief time walking alive once more in the green woods, together they passed, long ago, beyond the confines of this world. So it is that Lúthien Tinúviel alone of the Elf-kindred has died indeed and left the world, and they have lost her whom they most loved.

J.R.R. Tolkien