I translated a poem about poetry written by Baltasar de Alcázar several centuries ago. You can read all 100 lines in
The Alabama Literary Review (scroll to page 100 or so), but here's the beginning:
About Rhymes
....I'd like to tell my tale of woe,
oh Juana, but my curse is,
what I mean to say, I fear,
my verse sometimes reverses.
....For if I try to say what seems
important, half the time
I end up saying something else
because I'm forced to rhyme.
....Example: I would like to write
a verse to make it plain
Inez is
good and
lovely, but
the rhyme then adds
insane.
....And so I end up calling her
insane because it went
with
plain to make a rhyme although
that isn't what I meant.
....And if I praise the subtle wit
with which she's known to speak,
before I turn around, my rhyme
proclaims her nose a
beak.
....And thus in substance I allege
her nose, that's so sublime,
is hooked, although I have no cause
except the cause of rhyme.