It depends.Ptolemy was one of the most famous astronomers who was convinced that or solar system was geocentric, or revolving around the earth. Then, Copernicus came around, along with Galileo, and the attempted to convince people that that wasn't true, but that we were revolving around the sun. In fact, if you're writing an essay, a good point to add would be that Galileo spent a large part of his life imprisoned for "disobedience of the (Roman) Gods.)"