Johannes de Grocheio (or Grocheo) (Ecclesiastical Latin: [jɔˈan.nɛs dɛ ɡrɔˈkɛj.jɔ]; c. 1255 – c. 1320) was a Parisian musical theorist of the early 14th century. His French name was Jean de Grouchy, but he is best known by his Latinized name. He was the author of the treatise Ars musicae ("The Art of Music") (c. 1300), which describes the functions of sacred and secular music in and around Paris during his lifetime.[1]