I think you may be confusing heliocentrism with "round" earth? The ancient Greeks and (nearly) everyone since believed in a round earth. They also believed in g

I think you may be confusing heliocentrism with "round" earth? The ancient Greeks and (nearly) everyone since believed in a round earth. They also believed in geocentrism. And Copernicus had the broadly right idea, but convinced very few people since his idea was wrong. Kepler is the one who really convinced people that heliocentrism, because his model was quite accurate in its predictions and was thus able to overcome Aristotle's arguments for geocentrism.