A Petrarchan sonnet, also known as an Italian sonnet, consists of 14 lines divided into two parts: an octave and a sestet. The octave typically follows the rhyme scheme ABBAABBA, while the sestet can vary, often using patterns like CDCDCD or CDECDE. This structure allows for a clear presentation of a problem or theme in the octave, followed by a resolution or reflection in the sestet. The form is named after the poet Petrarch, who popularized it in the 14th century. Petrarchan sonnets often explore themes of love, nature, and human emotion, making them a favored choice for many poets throughout history, including Shakespeare and Milton.