as beautiful, and by others, distasteful. John of Salisbury (1120–1180), philosopher and Bishop of Chartres, who taught at the University of Paris during the years of Léonin but before Pérotin, was one of the latter. He attended many services at the Notre-Dame Choir School. In his Policraticus he offers a first-hand description of what was happening to music in the High Middle Ages, writing: References Further reading History of Music at Notre-Dame de Paris (in French) Bradley, Catherine A. 2018. Polyphony in Medieval Paris: The Art of Composing with Plainchant. Cambridge University Press. Gleason, Harold and Becker, Warren. Music in the Middle Ages and Renaissance (Music Literature Outlines Series I). Bloomington, Indiana. Frangipani Press, 1986. () "Notre Dame School," "Organum," "Léonin," "Pérotin," in Sadie, Stanley ed. The New Grove Dictionary of Music and Musicians. 20 vol. London, Macmillan Publishers Ltd., 1980. () Composition schools French music history Notre-Dame de Paris Medieval Paris Music organizations based in France Ars antiqua