Western music was divided into six eras according the styles and features in each of them.

The first one was the Medieval Era(中世紀 800-1400).
Music in this era was a huge repertoire of chants which developed during the first centuries of the Christian church.
Dufay, Guillaume (1400-1474), de Vitry, Phillipe (1291-1361) and de Machaut, Guillaume (1300-1377) were three composers in this era.