Anonymous IV was an English student working at Notre Dame in Paris, most likely in the 1270s or 1280s. Nothing is known about his life, not even his name. His manuscripts survive in two partial copies from Bury St. Edmunds; one from the 13th century, and one from the 14th.
Along with Johannes de Garlandia and Franco of Cologne, whose work precedes his, Anonymous IV's writings are the main source for understanding the Notre Dame school of polyphony. He is mainly famous for having written about Leonin and Pérotin, thereby assigning names to two of the composers of the music of the Notre Dame school who otherwise would have been anonymous; Leonin and Pérotin are among the earliest European composers whose names are actually known. Although they probably died at least fifty years before he was writing, he describes them as though they were still famous by name and part of a living tradition at the time.
In addition to mentioning Leonin and Pérotin as the best composers of organum, Anonymous IV mentions the work of the theorist Franco of Cologne, and gives descriptions of organum, discantus, rhythmic modes, rules for use of consonance and dissonance, notation, and genres of composition.
Sources and Further Reading
Richard H. Hoppin, Medieval Music. New York, W.W. Norton & Co., 1978. (ISBN 0393090906)
Harold Gleason and Warren Becker, Music in the Middle Ages and Renaissance (Music Literature Outlines Series I). Bloomington, Indiana. Frangipani Press, 1986. (ISBN 089917034X)
Articles "Anonymous theoretical writings," "Organum," "Leonin," "Perotin," The New Grove Dictionary of Music and Musicians, ed. Stanley Sadie. 20 vol. London, Macmillan Publishers Ltd., 1980. (ISBN 1561591742)
Through the writings of AnonymousIV we learn of the variety of music sung in daily services, the names of the great composers Leonin and Perotin, and that their style of music had already formed the mainstay of the cathedral repertoire for the best part of a hundred years.
Moreover, AnonymousIV names specific singers who were masters of their art, giving rise to the probability that this repertoire would have been well-known in abbeys and cathedrals throughout England, Wales, and Scotland.
AnonymousIV tells us about two of the most important composers of the fifty years either side of 1200: Leonin and Perotin.