It resembles a Gregorian chant, but unlike most music of the time, it does not draw on the existing repertory.
Plainchant
a feast day for the Virgin Mary... I think...
Probably in the early 13th century, close to 1200. It's included in W2 along with several three-part conducti and organi from the "Notre Dame school" of polyphony. I recall reading that the text of...
it's because it starts with the letter "O" and its easier 2 remember when u do Equations