Sestina

The sestina is a complex fixed form of six six-line stanzas and a concluding tercet (envoi), in which, instead of rhyme, a system operates of repeating the same six end-words in a strictly defined order that changes from stanza to stanza by the principle of retrogradatio cruciata ("backward crossing"). The sestina is credited to the Provençal troubadour Arnaut Daniel (c. 1200) and was perfected by poets of the Italian Renaissance. The form rests not on consonance but on the "rolling over" of key words which, returning in new contexts, acquire each time a different semantic shade. The sestina demands extraordinary versification discipline and is considered one of the most refined fixed forms of European poetry, attractive to masters of complex technique.