Plato describes it as a sphere in Timaeus (although typically, this is because a sphere is the most perfect and uniform shape), and says it revolves ("And because for its revolution it needed no feet he created it without feet or legs"). I think Eratosthenes made a pretty good stab at calculating the diameter.
He did, but the earlier Greeks—Thales of Miletus and Anaximander, both dating from the early sixth century BCE—did not think that the world was round.
The real clinchers in evidence for a round Earth are the ships' masts becoming visible before the ships themselves; and the Earth casting a circular shadow on the Moon during lunar eclipses, no matter what the orientation of the Earth with respect to the Moon. I wrote a story once (of which ewx may possibly have read an early version) narrated from the perspective of a flat-Earther in the time of Columbus (by which time everyone and his dog knew the Earth was round—even in the time of the Church Fathers, Cosmas Indicopleustes and Lactantius were laughed out the building for trying to revive flat-Earth cosmology), the narrator of which went to great lengths to explain these phenomena without recourse to a round-Earth cosmology.
To be fair though, Thales and Anaximander's cosmic theories were a bit... strange, even by pre-Socratic standards.
But I'm not sure about Babylonians or other early societies (but I bet Wikipedia knows!) - as you point out, seafaring nations might be the ones more likely to notice the phenomena that tell you the world is round.
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(no subject)
Date: 2008-02-15 03:34 pm (UTC)(no subject)
Date: 2008-02-16 07:06 pm (UTC)The real clinchers in evidence for a round Earth are the ships' masts becoming visible before the ships themselves; and the Earth casting a circular shadow on the Moon during lunar eclipses, no matter what the orientation of the Earth with respect to the Moon. I wrote a story once (of which
(no subject)
Date: 2008-02-17 03:09 pm (UTC)But I'm not sure about Babylonians or other early societies (but I bet Wikipedia knows!) - as you point out, seafaring nations might be the ones more likely to notice the phenomena that tell you the world is round.