The Ptolemaic Model of Circular Orbits

Ptolemy adopted the idea of that each planet and also the sun orbited around the earth on a perfect circle. But it had been observed even in the time of Ptolemy that sometimes the planets sort of move backwards across the sky. And this couldn't be explained by the Aristotelian worldview of perfectly circular orbits. The Copernican model could explain retrograde motion. So you can think of sort of Mars just slowly orbiting the sun further out and earth coming in from behind and overtaking Mars then moving past it again.