Sonnets are poems with 14 lines, usually with 10 syllables in each line, following the traditional English rhythm of unstressed and stressed beats called iambic pentameter. Like haiku, sonnets are strong examples of poetry with a strict form, as opposed to free verse, which allows for unrestricted use of rhyme and stanza structure. The significance of the sonnet is closely linked to this form and how it has been used by authors. Rhyme schemes vary, but notable types have developed throughout literary history.
The most prominent types of sonnets in English are the Italian or Petrarchan sonnet and the English or Shakespearean sonnet. The Petrarchan sonnet consists of one eight-line stanza (an octave) followed by one six-line stanza (a sestet), traditionally with a rhyme scheme such as abbaabba cdecde. The English sonnet consists of three four-line stanzas (quatrains) followed by a single two-line stanza (a couplet), following a rhyme scheme of abab cdcd efef gg. The Spenserian sonnet is another prominent type of English sonnet, which has a traditional rhyme scheme of abab bcbc cdcd ee.
According to the Folger Shakespeare Library, sonnets first became prominent during the 14th century when the form used by Petrarch became significant in Italy. The form then spread during the Renaissance to England, Portugal, Spain, Germany, and France, and in Elizabethan England, Shakespeare mastered the sonnet in the English language. During the Romantic period in Germany, the work of August Wilhelm von Schlegel gave sonnets significance in the German literary tradition. After Shakespeare and the English Renaissance, the sonnet form continued to be used in poetry, but it was not until the work of writers during the English Romantic period like William Wordsworth that they became popular again. It remained a significant poetic form in the 20th century through the work of American poets such as Robert Frost, Edna St. Vincent Millay and Gwendolyn Brooks.
Dating back to Petrarch, traditional sonnets contain strong themes of love. Petrarch discussed unattainable love and the pain that it can bring, and English poets such as Shakespeare followed this example during his time. While sonnets often discuss the difficulties of love, other themes are also appropriate. According to the Folger Shakespeare Library, Petrarch’s sonnets also explored the notion that poems, and art works in general, will outlive their creators.
Sonnets remain significant because they offer examples of how strict, formal poetry can also offer some flexibility to authors. For example, switching the rhythm of a sonnet’s typical unstressed/stressed pattern to a stressed/unstressed pattern in one line draws attention to the line and does not violate the more important formal requirements such as stanza length. Contemporary poets have used the traditional rules of line, rhythm and rhyme and the opportunity to bend these rules as a way to add new meaning and unique expression to their poetry.