Fourteenth-century Italian poet Francesco Petrarch is credited with inventing the Petrarchan sonnet, a strict, formal poetic form introduced into English poetry in the sixteenth century. The Petrarchan sonnet, also called the Italian sonnet, contains fourteen lines written in iambic pentameter and a careful rhyme scheme. Understanding the structure of a Petrarchan sonnet is essential to writing this type of poem.
Petrarchan sonnets contain 14 lines written in iambic pentameter, a rhythm that contains five "feet." Each foot contains an unstressed and a stressed syllable. These lines are split into two sections: an octet, or eight-line section, and sestet, or six-line section. The octet typically has a rhyme scheme of abbaabba, although it may also have an abbacddc or abababab scheme. Sonnets with different rhyme schemes in the quatrains of the octet are sometimes called envelope sonnets. The sestet may have an xyzxyz or xyxyxy pattern. The other common type of sonnet -- the English or Shakesperian sonnet -- has three quatrains and a couplet.
Petrarchan sonnets begin by describing a subject or problem, such as love, faith or another emotion. Around the end of the octave, the poet presents the turn, or volte, which is a thematic shift in direction. This turn is often indicated by "however," "but" or "yet." The sestet develops or answers the tension or problem established in the octave and shifted in the turn.
Petrarchan sonnets often include metaphors or similes, which are comparisons between unlike objects or ideas. They may also include conceit, a type of extended metaphor that refers to the surprising comparison between dissimilar things. For example, the extended metaphor of love as a battle is an example of conceit. Poets also often employ personification in these sonnets, which is the attribution of human qualities to something non-human.
Composing a Sonnet
If you want to compose a Petrarchan sonnet, first make sure you are familiar with iambic pentameter. Next, let the structure of the sonnet function as an outline. Start with your subject and the tension and don't write the turn until you get to the end of the sonnet. The turn comes naturally to many poets, according to the University of Northern Iowa, especially after you have built up the tension in the rest of the poem. Sonnets are often written about love, but they can be written on any topic. If you have more to say than you can fit in one sonnet, consider writing a series of sonnets, as many poets did.