From a reader:
Hi Jonah,
Just to add my little tidbit: in the Talmud there is a throwaway reference to a great Jewish sage who argued with a rabbi about the accuracy of his calculation of the earth’s circumference (this sort of thing was taken very seriously in the diaspora because it was related to the calculation of the new moon, and hence the Jewish calendar and observance of holidays.) Don’t remember when that part was written, but the whole of the Talmud was codified by the 5th century, so there’s a group of people who were in no doubt as to the shape of the earth at least a millennium before Columbus.