Compilatio Magister

Little is known about Léonin beyond the fact that he seems to have had a bent for composing erotic poetry. The somewhat unhelpfully named 'Anonymous IV', a monk from Bury St Edmunds, tells us of two 'masters'—Leoninus and Perotinus—who dominated the twelfth-century musical world. Both were reputedly based at Notre Dame in Paris, and Leoninus was responsible for the Magnus liber organi, the 'Big Book of organum' (an organum being a polyphonic setting of plainchant), which is widely regarded as the single greatest achievement in the development of early polyphony.