Vitruvius Quote

It was left by Aristoxenus, who with great ability and labour classified and arranged in it the different modes. In accordance with it, and by giving heed to these theories, one can easily bring a theatre to perfection, from the point of view of the nature of the voice, so as to give pleasure to the audience.

Chapter V, Sec. 6 - De architectura (The Ten Books On Architecture) (~ 15BC) - Book V