What is Death?

Looking on a page where stood Graven of old on old-world wood Death, and by the grave's edge grim, Pale, the young man facing him, Asked my well-beloved of me Once what strange thing this might be, Gaunt and great of limb.
Death, I told him: and, surprise Deepening more his wildwood eyes (Like some sweet fleet thing's whose breath Speaks all spring though nought it saith), Up he turned his rosebright face Glorious with its seven years' grace, Asking—What is death?