If men should ask, Despoina, why I tell
Of nothing glad nor noble in my verse
To lighten hearts beneath this present curse
And build a heaven of dreams in real hell,

Go you to them and speak among them thus:
“There were no greater grief than to recall,
Down in the rotting grave where the lithe worms crawl,
Green fields above that smiled so sweet to us.”

Is it good to tell old tales of Troynovant
Or praises of dead heroes, tried and sage,
Or sing the queens of unforgotten age,
Brynhild and Maeve and virgin Bradamant?

How should I sing of them? Can it be good
To think of glory now, when all is done,
And all our labour underneath the sun
Has brought us this-and not the thing we would?

All these were rosy visions of the night,
The loveliness and wisdom feigned of old.
But now we wake. The East is pale and cold,
No hope is in the dawn, and no delight.

Clive Staples Lewis

http://www.poemhunter.com/poem/apology-8/