Pérotin (fl. c. 1200) was a composer associated with the Notre Dame school of polyphony in Paris and the broader ars antiqua musical style of high medieval music. He is credited with developing the polyphonic practices of his predecessor, Léonin, with the introduction of three and four-part harmonies.Other than a brief mention by music theorist Johannes de Garlandia in his De Mensurabili Musica, virtually all information on Pérotin's life comes from Anonymous IV, a pseudonymous English student.