The villanelle originated in Spain and Italy as a ballad-like folk song without a strict format or length. Its current structure wasn’t widely used until the 19th century, when it was popularized by French poet and author Théodore de Banville (1823-1891).
The villanelle, a 19-line poem consisting of five tercets (three-line stanzas) and a final quatrain (four-line stanza), has two refrains. The first and third lines of the first stanza are rhyming refrains. They alternate as the third line in the stanzas which follow, and they appear as a couplet—the final two lines—in the quatrain at the end of the poem.
Since the two refrains (repeating lines) play have such an important role in a villanelle, many poets write the refrains first, and fill in the other lines after that. As with many other modern-day poetic forms, most villanelles are now written in English.