In Li tresor, Brunetto explains in detail the fact that Earth is round. But he does so, curiously to the eyes of a modern reader, in terms of “intrinsic” rather than “extrinsic” geometry. That is to say, he does not write: “Earth is like an orange,” as Earth would look if seen from the outside, but writes instead: “Two knights who could gallop sufficiently far in opposite directions would meet up on the other side.”
