JOHANNES de MURIS. — Astronomer, mathematician, philosopher, and music theorist, born in Normandy before 1300 and died in 1351.
He was at the Sorbonne in Paris, where it has been thought that he served as rector (a Julianus de Muris appears as rector there in 1350); canon at Mezières (Bourges) in 1344; he participated in the work for the reform of the calendar as an astronomer under Clement VI in Avignon. He corresponded with the other great French theorist, Philippe de Vitry, whose theories he defended. The *Speculum musicae* (recognized as the work of Jacques de Liège) and the *Summa musicae* are not his. He is, however, the author of the *Ars novae musicae* (1319) and *Musica speculativa* (1323), in which he appears as a far-sighted and brilliant precursor of new theories, with a prominent position, especially in the field of emerging polyphony. His works are edited in M. Gerbert, *Scriptores ecclesiastici de musica sacra*, III, St. Blasien 1784, pp. 292-97, 300-301; and in D. de Coussemaker, *Scriptores*, III, Paris 1870, pp. 398-401 (*Anonymus*, VI), *Conclusions*, III, pp. 109-13. An English translation of the *Ars novae musicae* is found in O. Strunk, *Source readings in music history*, New York 1950, pp. 172-79.