Petrarch was famous – almost infamous – for writing a certain type of poem. The following example, from my World Lit textbook, should demonstrate ably.

(Transcribed from the excerpts from Petrarch's Rhymes, reprinted in Literature of the Western World, edited by Brian Wilkie and James Hurt, published by Prentice Hall):

XC
Upon the breeze she spread her golden hair
that in a thousand gentle knots was turned
and the sweet light beyond all radiance burned
in eyes where now that radiance is rare;

and in her face there seemed to come an air
of pity, true or false, that I discerned:
I had love's tinder in my breast unburned,
was it a wonder if it kindled there?

She moved not like a mortal, but as though
she bore an angel's form, her words had then
a sound that simple human voices lack;

a heavenly spirit, a living sun
was what I saw; now, if it is not so,
the wound's not healed because the bow goes slack.

In particular, notice the extreme hyperbole concerning Petrarch's lover's features. He did this a lot, and a lot of people copied him, to the extent that Shakespeare parodies this sort of thing a couple hundred years later in his Sonnet 130, with lines such as "My mistress' eyes are nothing like the sun; / coral is far more red than her lips' red;"