Before 1450 - Rhythmic independence of voices in Polyphonic texture.
This era is often referred to as Gothic or Medieval period. Church music was dominated by Gregorian Chant, a homophonic (one-voiced, that is, unison) form that could trace its origins back to the ancient Hebrew Temple in Jerusalem.
But in this period we start to see the beginnings of modern polyphonic (multi-voiced) music, as western musical art begins to differentiate from the music of the east.
Popular music was performed by singers and instrumentalists variously known as jongleurs, troubadours, trouveres and the Minnesinger.
While the names of most composers of this time have been lost, there are some that have survived: Abbess Hildegard von Bingen, Perotin Magnus, and Guillaume de Machaut, to name a few.