Fixed verse form having 14 lines that are typically five-foot iambics rhyming according to a prescribed scheme. The sonnet is unique among poetic forms in Western literature in that it has retained its appeal for major poets for five centuries. It seems to have originated in the 13th century among the Sicilian school of court poets. In the 14th century Petrarch established the most widely used sonnet form. The Petrarchan (or Italian) sonnet characteristically consists of an eight-line octave, rhyming abbaabba, that states a problem, asks a question, or expresses an emotional tension, followed by a six-line sestet, of varying rhyme schemes, that resolves the problem, answers the question, or resolves the tension. In adapting the Italian form, Elizabethan poets gradually developed the other major sonnet form, the Shakespearean (or English) sonnet. It consists of three quatrains, each with an independent rhyme scheme, and ends with a rhymed couplet.