“Shall I compare thee to a summer’s day?” is a poem in the form of a Petrarchan sonnet—that is, a 14-line rhyming ode. While Petrarch’s odes to a real or imaginary “Laura” focused only on his obsessive idealization of a woman whom he could not have, and probably only desired expressly for her unattainability, Shakespeare’s ode has an unnamed object. It is also possible that the poem is less focused on an actual person than it is on a feeling or concept.

Further, as earlier noted, the form of the sonnets differs between Petrarch and Shakespeare. The former form is arranged as an octave (eight lines) and a sextet (six lines) with an ABBA-ABBA-CDCDCD or CDEEDE rhyme scheme, while the latter is often arranged as three quatrains (four lines apiece) and a concluding couplet (two lines) with an ABAB-CDCD-EFEF-GG rhyme scheme. This arrangement has—at least in part—to do with the language in which the poems were written as rhymes differ in varying languages.

The Shakespearean, or Elizabethan, sonnet was more intellectually inspired than the sonnets—from both Italy and France—preceding it.