Ars Nova Musicae

Philippe de Vitry, a French theorist, poet, philosopher and composer, wrote a treatise on music in 1322 that changed the way music was written and expressed. It was entitled Ars Nova notandi, a new technique in writing music. We use this moment as the line to divide two eras of music. Ars nova is a musical style which flourished in the Kingdom of France and its surroundings during the Late Middle Ages. The term is used relative to the preceding ars antiqua and the ars subtilior which came after.

The differences in the music of these writing techniques are subtle to our modern ears, but the innovations of de Vitry’s new system allowed for increased rhythmic freedom and expression to the composer. A good analogy would be the use of perspective in the visual arts; the use of foreground and background. No longer were all of the voices in music on the same rhythmic plane, they now had greater independence from each other.

One of the most prominent composers of the Ars Nova style was Guillaume De Machaut, another French poet and composer who was a little younger than de Vitry.

His work, Messe de Nostre Dame, is the earliest complete Mass of which we are aware written by a single composer. This is significant because it stands as an example of music taking on the personality of an individual. Machaut used the tools of the Ars Nova to create a work that was unified and expressive. He put his stamp on it; he made it personal. In addition to being written as a form of worship at Mass, the De Machaut Mass stands as an object of art by itself, a personal expression of an individual. That’s what the innovations of de Vitry and the Ars Nova movement allowed.

https://en.wikipedia.org/wiki/Ars_nova

https://www.vermontpublic.org/vpr-classical/2015-06-15/timeline-008-ars-nova-versus-ars-antiqua