[Bernard Marx]

The calculations of the Earth’s size by Eratosthenes and and Ptolemy differed considerably

I know all that, and you completely miss the essential point: both knew the Earth is spherical some 2,200 years ago.

[Sherman Logan]

I quite agree, as I’ve said on this thread several times.

The Chinese, until recent times, apparently believed the world was flat, perhaps because of the limited contact their intellectuals had with the sea.

But it’s probable all educated people in seafaring nations have for a very long time known the world is spherical.