The sonnet form
“Sonnet 18” follows the structure of the English sonnet. The sonnet was originally invented in Italy in the 13th century and used as a format for love poetry. In the 16th century, an English version of the sonnet form was developed, and this is what Shakespeare uses. This form is often referred to as the Shakespearean sonnet.
The English sonnet has fourteen lines, divided into three quatrains (four-line stanzas) followed by a couplet (two-line stanza). The couplet often reinforces the thoughts presented in the quatrains, and this goes for “Sonnet 18”, too.
In the first twelve lines, the poet debates whether the young man can be compared to a summer’s day be...