I have no background whatever in the history of music and therefore no factual material to add. I do, however, have a question for the truly scholarly historians among you.

Up until the time of the Great Schism (nominally 1054) most Christian Liturgical music was sung in the Byzantine "tones" and the chants commonly used notes that are not only strange to the modern western ear but included notes that are "in the cracks" on a piano. Do you think it possible that following the Great Schism, the Western Church made rules against the tones and chants of the Eastern Church? Many of the "Devil tones" people have contributed here are commonly found in Eastern music.

Just a suggestion.

      - Mark