Our modern understanding of planetary motion had its beginnings around 350 B.C. in ancient Greece, when Plato—and Aristotle soon after him—proposed the geocentric model of universe; that is, the theory that everything in the sky revolved around the Earth in a perfect circular motion. Although we now know this to be incorrect, the system seemed plausible and was quite successful at predicting much of what went on in the sky. Although, looking at this animation of an Earth-centered solar system, it's remarkable that any clear patterns could be detected at all!