Pérotin 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.

Polyphony is a type of musical texture consisting of two or more simultaneous lines of independent melody, as opposed to a musical texture with just one voice (monophony) or a texture with one dominant melodic voice accompanied by chords (homophony).