You have ask'd for a verse:--the request
In a rhymer 'twere strange to deny;
But my Hippocrene was but my breast,
And my feelings (its fountain) are dry.

Were I now as I was, I had sung
What Lawrence has painted so well;
But the strain would expire on my tongue,
And the theme is too soft for my shell.

I am ashes where once I was fire,
And the bard in my bosom is dead;
What I loved I now merely admire,
And my heart is as grey as my head.

My life is not dated by years--
There are moments which act as plough;
And there is not a furrow appears
But is deep in my soul as my brow.

Let the young and the brilliant aspire
To sing what I gaze on in vain;
For sorrow has torn from my lyre
The string which was worthy the strain.

George Gordon Byron

http://www.poemhunter.com/poem/to-the-countess-of-blessington/