Some ancient Greek who went by the name Erosathenes (check spelling) is the one first credited for bringing it to the publics attention. But I have a hunch there were quite a few ancient peoples possibly even prior to him, who kind of already had a hunch themselves that the Earth wasn't exactly cylindrical or triangular or even flat in shape.
I was thinking it was Galileo until I ran upon this while researching. Among the ancient Greeks, Homer thought the world to be flat. In contrast, Pythagoras postulated that the earth was round. A century later, Aristotle sided with the theory of the roundness of the earth. Leave it to the clever Greek investigator Eratosthenes to bring it all together with a calculation (and a remarkably accurate one!) about the diameter of the earth, and also the inclination of its axis of rotation to its orbital plane about the sun. I thought this was very interesting.
9 months ago
Last edited at 7:03PM on 3/29/2013
Pythagoras was the first to think the Earth was round in 570 B.C. When the Greeks made marble statues of the god Atlas, he was never depicted holding up the sky like in the stories, but he was holding up the Earth... a spherical Earth. Eratosthenes was the first person to prove that the Earth was round by finding the circumference of it. In the Age of Exploration, Ferdinand Magellan was the first to circumnavigate the globe, which I guess is the only real way to tell if it's round.