To recap from earlier posts, thanks to other early composers as Léonin and Pérotin, the organum-style polyphony (heterophony) or ars antiqua (old style) laid the foundations for the later polyphony. The secondary voices moving in parallel to the main vocal line was called conductus. By the 13th century, conductus was replaced by the motet which introduced counterpoint that produced striking harmonies of exquisite beauty. Meanwhile, secular song such as those performed by the French troubadours was also evolving due to being written down. Various composers began dissecting them to incorporate into their own styles and by the 14th century ars nova (new style) was born mainly due to the efforts of theorist Philippe de Vitry (1291-1361) who served as a bishop but, like Hildegard, had a wide range of interests as philosopher, poet, writer, critic and composer. He was widely traveled and enjoyed great renown for his writings. His book, Ars nova, introduced the use of the minim or half-note and he is regarded by many to be the inventor of ballade. His work was a huge influence on Guillame de Machaut whom we have discussed in earlier posts.
Léonin - Christus Resurgens - YouTube
Pérotin was active in the 12th century but we don’t know when or where he was born or when or where he died (some believe he may have been a high-ranking official at the cathedral of Notre-Dame named Petrus but there is no evidence Pérotin actually had anything to do with Notre-Dame). We know Pérotin edited the Magnus liber of Léonin (about whom similarly little is known) leading some to believe he could have been a student of Léonin. This book was a very early work of musical notation containing the chants used at Notre-Dame in the late 1100s and is one of the first to be written about the use of harmony. Pérotin was greatly influenced by this book and was the first composer known to compose in more than two independent parts. He composed at least two four-part compositions and a dozen pieces for three parts. Pérotin also composed about 160 clausulae or polyphonic passages inserted into plainchants to break up the monotony. No doubt he had a lot to do with the development of the motet which emerged in his lifetime although it is not known if he ever composed in that style. His material has a surprisingly modern sound; certainly a departure from other organum compositions of that time:
Pérotin "Alleluia nativitas" - YouTube
Another important early composer (and astronomer) was John Dunstable (1390-1453) who enjoyed great success and international renown as a composer of masses, carols and motets which are not only stunningly beautiful but were extremely influential in continental Europe. He was one of the first composers to exploit the use of third and sixth intervals which became a distinctive English musical trait. Due to the popularity of his compositions, we know that by 1436 he was a wealthy man. In the decade before his death, Dunstable was, by far, the leading composer of England. His pieces continued to have great influence well after his death.
John Dunstable: Motets - Salve Regina misericordiae - YouTube