I confess I hadn't thought of a couple of those.
I think the best argument that it had always been known the the world is round is that you can see it's round. This is easiest to see on a slight elevation above a large body of water with a straight edge. Just hold it out at arms lenght to the horizon and you can clearly see the earth dip away on both ends.
I have little doubt many animals know the planet is a sphere.