Petrarchan sonnets, also called Italian sonnets, were made popular by Petrarch, a poet of the 1400s, who wrote poems of unrequited love. The structure of his sonnets consists of fourteen lines: first an octave (which is eight lines) with a specific rhyme scheme abbaabba, followed by a sestet (six lines) with a more flexible scheme.
In the octet, the woman, Laura, is described in intense, exaggerated detail as "the sweet light beyond all radiance," thus introducing the theme of the sonnet. It becomes apparent that no physical love exists as the line "love's tinder in my breast unburned" indicates. The problem is thus introduced to the reader.
The sestet usually resolves the problem whereas in Petrach's Sonnet 90 it reveals the permanence of his problem. His love will never be realized as "the wound's not healed," revealing his very real pain despite her transience - "she bore an angel's form."
Petrarch indicates that she is no longer in his midst and his tone is wistful - she has an almost 'heavenly spirit" -even though thoughts of her almost make him ill.
There are various translations of the sonnet but Petrarch's influence is undisputed. Shakespeare recognized his art form when composing his own earlier poetry and even his plays.