Tithonus by Alfred, Lord Tennyson is a hauntingly beautiful dramatic monologue told in the voice of Tithonus. This story is based on an ancient Roman myth of Aurora, goddess of dawn, falling in love with the Trojan prince Tithonus. The gods grant him eternal life at her request, but she forgets to add a request for eternal youth, and thus he is condemned to aging forever.
The first thing that strikes the critic is how well the theme suits the tone of reflective melancholy that Tennyson does so well, using rhythm and other sonic devices to produce and effect of languor, and longing for the eternal beauty of the goddess.
On an thematic level, the critic can appreciate how this works as a counterpoint to "In Memoriam". If Hallam's premature death was a tragedy, in another way, its opposite, prolonged life, is equally problematic, especially outliving the powers of one's youth, as seen here and in "Ulysses."