The two kinds of public games, then, have one origin; and they have common names, as owning the same parentage. So, too, as they are equally tainted with the sin of idolatry, their foundress, they must needs be like each other in their pomp. But the more ambitious preliminary display of the circus games to which the name procession specially belongs, is in itself the proof to whom the whole thing appertains, in the many images the long line of statues, the chariots of all sorts, the thrones, the crowns, the dresses.
What high religious rites besides, what sacrifices precede, come between, and follow. How many guilds, how many priesthoods, how many offices are set astir, is known to the inhabitants of the great city in which the demon convention has its headquarters. If these things are done in humbler style in the provinces, in accordance with their inferior means, still all circus games must be counted as belonging to that from which they are derived; the fountain from which they spring defiles them.
The tiny streamlet from its very spring-head, the little twig from its very budding, contains in it the essential nature of its origin. It may be grand or mean, no matter, any circus procession whatever is offensive to God. Though there be few images to grace it, there is idolatry in one; though there be no more than a single sacred car, it is a chariot of Jupiter: anything of idolatry whatever, whether meanly arrayed or modestly rich and gorgeous, taints it in its origin.
Source: De Spectaculis (The Shows) (New Advent)