"Pérotin[n 1] (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 who probably studied in Paris. Anonymous IV names seven titles from a Magnus Liber—including Viderunt omnes, Sederunt principes and Alleluia Nativitas—that have been identified with surviving works and gives him the title Magister Perotinus (Pérotinus the Master) meaning he was licensed to teach. It is assumed that Perotinus was French and named Pérotin, a diminutive of Peter, but attempts to match him with persons in contemporary documents remain speculative." - (en.wikipedia.org 20.11.2023)
