Medieval French composer Philippe de Vitry (1291-1361) was principally known in his time as a poet, but was also a music theorist and composer credited for shortening note values and introducing new ways to notate rhythm in the treatise Ars Nova (1322). None of Vitry's secular compositions survive, but about 14 sacred motets by him are known in addition to a number of others considered of questionable authenticity; Vitry was an early practitioner of the Isorhythmic motet. Vitry was also a cleric and soldier who served the Duke of Normandy; Vitry was appointed Bishop of Meaux in 1351 by Pope Clement VI.