Let us now go back towards the beginnings of Western music history. Here’s a quick thumbnail sketch — the music of Ancient Greece and Rome was much written about (Plato famously had some very specific opinions about it) but was generally not recorded with any kind of notation system. Thus, it is pretty much impossible to reconstruct what it sounded like.
Gregorian chant emerged around the 4th century AD as the first notated music. The Church was very interested in standardizing a cycle of daily rituals which included both recited texts and music. Writing melodies down allowed them to achieve this goal and facilitated coordinated group performance. It was, of course, stuff that sounded (and looked) like this:
In chant, single lines of melody flow in a somewhat relaxed, loose rhythm.
The “Notre Dame School” was a community of musicians in and around the Cathedral of Paris, Notre Dame, who began to create music in which one or more parts is added to a chant melody. In general, the chant melody tends to slow down to a crawl, and the added parts swirl around it in a more active rhythm. (This is the first polyphonic music in the Western tradition.)
Pérotin (ca. 1170-1236) was one of these composers.
What’s interesting about these very early works is that musicians did not yet have the same concept of consonance, (i.e. rules about what sounds went well with each other) that would govern music for centuries. Thus, they make sonorities that sound very Modern to our ears.
The Hilliard Ensemble’s recording is featured in the above youtube, and I think it is your best opportunity to hear this music in an impeccably crisp and clear rendition. Ariama Archivmusik Amazon MP3 Amazon CD eMusic