A sestet is six lines of poetry forming a stanza or complete poem. A sestet is also the name given to the second division of an Italian sonnet (as opposed to an English or Spenserian Sonnet), which must consist of an octave, of eight lines, succeeded by a sestet, of six lines. The first recognized and documented user of this poetical form was the Italian poet Petrarch. In the usual course the rhymes are arranged ABCABC, but this is not necessary.