A further observation on this issue is that Dante certainly has a spherical
earth in his Commedia, which was written around 1310. He doesn't treat this
as controversial at all, but simply takes it as fact. His passage on what
happens to gravity when one passes the center of the earth is famous (he
didn't understand that gravity would get weaker as one approached the
center, so he has the direction do a sudden flip). He imagines that the
"other hemisphere" is mostly ocean, except for Mount Purgatory which sits
opposite Jerusalem.