A sonnet is a 14-line poem with a specific rhyme scheme. The form originated in Italy in the 13th century. Petrarch perfected it. Later, Shakespeare made it his own. The sonnet has been used for love, politics, religion, and satire.

The two main types are the Petrarchan and the Shakespearean. The Petrarchan sonnet has an octave and a sestet, rhyming ABBAABBA CDECDE. The Shakespearean sonnet has three quatrains and a couplet, rhyming ABAB CDCD EFEF GG. The volta—the turn—usually comes at line nine in the Petrarchan and line thirteen in the Shakespearean. The sonnet’s tight structure forces discipline. Poets have loved it for centuries because it makes them say more with less. Modern poets still write sonnets, sometimes breaking the rules deliberately. The form survives because it is both a challenge and a vessel.

Two main forms

• Petrarchan: octave + sestet
• Shakespearean: three quatrains + couplet
• 14 lines in iambic pentameter
• Volta: the turn or shift