Taking courage and looking forward from the standpoint of higher ideas born of the multiplication of the arts, they gave up huts and began to build h… - Vitruvius

In theatres... there are the bronze vessels in which are placed in niches under the seats in accordance with the musical intervals on mathematical principles. These vessels are arranged with a view to musical concords or harmony, and apportioned in the compass of the fourth, the fifth, and the octave, and so on up to the double octave, in such a way that when the voice of an actor falls in unison with any of them its power is increased, and it reaches the ears of the audience with greater clearness and sweetness. Water organs too, and the other instruments which resemble them cannot be made by one who is without the principles of music.

These rules for symmetry were established by Hermogenes, who was also the first to devise the principal of the pseudodipteral octastyle.

Owing to this favor I need to have no fear of want to the end of my life, and being thus laid under obligation I began to write this work for you, because I saw that you have built and are now building extensively, and that in future also you will take care that our public and private buildings shall be worthy to go down to posterity by the side of your other splendid achievements.