What led to the birth of polyphonic music?

The Notre Dame school trained a lot of famous singers in the Middle Ages. They were the first group of composers to bring Polyphony into the church. They cataloged a significant amount of music do that is why we know so much about music from the Middle Ages today.

        i think it is referred as the 8th wonder of the world because each of the terra cotta warriors was not the same. they each had many things with their physical stature, like different height, armor, and different characteristics, which were all different. what makes it interesting is that there were 8,000 soldiers in that tomb. so making that many soldiers for the emperor meant a-lot to the emperor. it means that their is strength in numbers now matter how different.

hope it : p

dc was afraid of these new companies because they may take their customers away due to them being more better or something else.