A sestina (sestina, from sesto, sixth; Old Occitan: cledisat klediˈzat; also known as sestine, sextine, sextain) is a fixed verse form consisting of six stanzas of six lines each, normally followed by a three-line envoi. The words that end each line of the first stanza are used as line endings in each of the following stanzas, rotated in a set pattern.
The invention of the form is usually attributed to Arnaut Daniel, a troubadour of 12th-century Provence, and the first sestinas were written in the Occitan language of that region. The form was cultivated by his fellow troubadours, then by other poets across Continental Europe in the subsequent centuries; they contributed to what would become the "standard form" of the sestina. The earliest example of the form in English appeared in 1579, though they were rarely written in Britain until the end of the 19th century. The sestina remains a popular poetic form, and many sestinas continue to be written by contemporary poets.
The oldest-known sestina is "Lo ferm voler qu'el cor m'intra", written around 1200 by Arnaut Daniel, a troubadour of Aquitanian origin; he refers to it as "cledisat", meaning, more or less, "interlock". Hence, Daniel is generally considered the form's inventor, though it has been suggested that he may only have innovated an already existing form. Nevertheless, two other original troubadouric sestinas are recognised, the best known being "Eras, pus vey mon benastruc" by Guilhem Peire Cazals de Caortz; there are also two contrafacta built on the same end-words, the best known being Ben gran avoleza intra by Bertran de Born. These early sestinas were written in Old Occitan; the form started spilling into Italian with Dante in the 13th century; by the 15th, it was used in Portuguese by Luís de Camões.
The involvement of Dante and Petrarch in establishing the sestina form, together with the contributions of others in the country, account for its classification as an Italian verse form—despite not originating there.