About 350 B.C., we have Aristotle , teacher of Alexander the Great. Aristotle made an argument for the earth's sphericity on the basis of the appearance of the earth's shadow on the moon during lunar eclipses. Also, he noted that different constellations are visible at different latitudes. Even in ancient times, one could watch a ship sail away towards the horizon, with the hull disappearing first, then the upper decks, then the sail, et c. In later ages, Magellan's expedition actually circumnavigated the earth, and today, of course, we can see the earth from space.
Bricks fall to earth because their natural state is to be at rest on the earth's surface.
Even an object thrown upward will slow, stop, and return to earth. An object slid across a table will slow and stop. However, it is the nature of celestial objects to move in perfect circles in the heavens, and so that is what they do. This idea, that earthly and celestial objects obey different laws, is an important point to which we shall return soon. Aristotle argued that the earth is at the centre of the universe, since all celestial objects circle the centre of the universe, and since earthly material is attracted toward the centre of the earth, the two centres must co-incide.