"Ode to the West Wind" is written in terza rima, a poetic form consisting of tercets—or groups of three lines of poetry—often written in iambic pentameter. These tercets have a particular rhyming pattern: the final word in the second line of each tercet creates the rhyme for the final word in the first and third lines in the next tercet. Visualized, this rhyme scheme can be expressed as aba, bcb, cdc, ded, etc. If this is confusing, just take a look at the first two stanzas of "Ode to the West Wind;" in the first stanza, "being" and "fleeing" rhyme, and the final word in the second line, "dead," provides the rhyme for the first and third lines of the next stanza ("red" and "bed"), and so on.
Shelley actually modifies this poetic form, which was originally invented by Dante Alighieri—the Italian poet most famous for the Divine Comedy—by dividing the poem into five sonnets of fourteen lines each. Each sonnet contains four stanzas of terza rima and concludes with a couplet (two lines), which uses the final word of the previous stanza's middle line as the basis of its rhyme. For example, the first sonnet concludes with the lines "Wild Spirit, which art moving everywhere; / Destroyer and preserver; hear, oh hear!" This couplet's rhyme, on "everywhere" and "hear," is based on the word "air," which is found at the end of the previous stanza's middle line. This form has been called the "terza rima sonnet."
Dante is thought to have been inspired in his creation of the form by the tercets used by the Provençal troubadours. These were skilled poets in the upper echelons of society in eleventh- through thirteen-century southeastern France. After Dante, the form was brought to England by Geoffrey Chaucer in his poem "A Complaint to His Lady." It has since been adopted by other poets throughout history. Some notable poems written in terza rima or variations of the form include Robert Frost's "Acquainted with the Night" (1928), Sylvia Plath's "Sow" (1957), and Adrienne Rich's "Terza Rima" (2001).
