Tennyson's poem relates the myth of Tithonus, a mortal man who was loved by Eos, the goddess of the dawn. Tithonus was exceedingly beautiful and Eos took him from the mortal realm to live in her palace in the East:
So glorious in his beauty and thy choice,
Who madest him thy chosen, that he seem'd
To his great heart none other than a God!
In their early state of bliss, Tithonus asked for a gift from Eos: immortality, so that he could be with her forever. Eos granted him immortality gladly, but forgot to grant him eternal youth as well. Tithonus is now condemned to age forever, far beyond the capabilities of the human body. His beauty has long since withered away with all his joy in life:
I ask'd thee, 'Give me immortality.'
Then didst thou grant mine asking with a smile,
Like wealthy men, who care not how they give.
But thy strong Hours indignant work'd their wills,
And beat me down and marr'd and wasted me,
And tho' they could not end me, left me maim'd
To dwell in presence of immortal youth,
Immortal age beside immortal youth,
And all I was, in ashes.
In the poem, Tithonus is begging Eos to let him die. He begs her every morning before she leaves to light the sky with the dawn, and every morning, she kisses him tearfully and gives him no answer:
Let me go: take back thy gift:
Why should a man desire in any way
To vary from the kindly race of men
Or pass beyond the goal of ordinance
Where all should pause, as is most meet for all?
[...]Thy cheek begins to redden thro' the gloom,
Thy sweet eyes brighten slowly close to mine [...]
Lo! ever thus thou growest beautiful
In silence, then before thine answer given
Departest, and thy tears are on my cheek.
Tithonus is afraid that Eos's silence does not mean that she will not help him, but that she cannot help him:
Why wilt thou ever scare me with thy tears,
And make me tremble lest a saying learnt,
In days far-off, on that dark earth, be true?
'The Gods themselves cannot recall their gifts.'
And yet, he pleads, she is a goddess; she has divine powers; surely she can do something. Surely in her daily course across the sky, she has seen his resting place; it must exist:
Release me, and restore me to the ground;
Thou seëst all things, thou wilt see my grave
The poem ends with Tithonus's forlorn wish to "forget these empty courts." He half-knows his wish will never be granted, but he can't help hoping anyway.