"Though he avoided outright endorsement of the view, fifth-century Church Father Saint Augustine was clearly familiar with the theory of the spherical earth: "They [those who believe that "there are men on the other side of the earth"] fail to observe that even if the world is held to be global or rounded in shape, or if some process of reasoning should prove this to be the case, it would still not necessarily follow that the land on the opposite side is not covered by masses of water.""

Source: Saint Augustine, Henry Chadwick (2008). “The Confessions”, p.217, Oxford Paperbacks