According to the Internet source given below, Pérotin, also called Perotin the Great, was a European composer, believed to be French, who lived around the end of the 12th and beginning of the 13th century. He was the most famous member of the Notre Dame school of polyphony and the ars antiqua style. He was one of very few composers of his day whose name has been preserved, and can be reliably attached to individual compositions; this is due to the testimony of an anonymous English student at Notre Dame known as Anonymous IV, who wrote about him and his predecessor Léonin. Anonymous IV called him "Magister Petronius" ("Pérotin the Master"). The title, employed also by Johannes de Garlandia, means that Perotinus, like Leoninus [Leonin]
, earned the degree magister artium, almost certainly in Paris, and that he was licensed to teach. The name Perotinus, the Latin diminutive of Petrus, is assumed to be derived from the French name Pérotin, diminutive of Pierre. The diminutive was presumably a mark of respect bestowed by his colleagues. He was also designated "magnus" by Anonymous IV, a mark of the esteem in which he was held, even long after his death.
||Brief biography by en.wikipedia.org.