Influences upon the Middle Ages
Lewis writes about Cicero's "Somnium Scipionis*":
Far more important [...] is the general character of this text, which is typical of much material which the Middle Ages inherited from antiquity. Superficially it seems to need only a few touches to bring it into line with Christianity; fundamentally it presupposes a wholy Pagan ethics and metaphysics. As we have seen, there is a heaven, but a heaven for statesmen. Scipio is exhorted to look above and despise the world; but he is to despise primarily 'the talk of the rabble' and what he is to look for above is the reward 'of his achievements'. It will be decus, fame or 'glory' in a sense very different from the Christian. Most deceptive of all is xxiv, where he is exhorted to remember that not he, but only his body, is mortal. Every Christian would in some sense agree. But it is followed almost immediately by the words 'Realise therefore that you are a god'. For Cicero that is obvious; 'among the Greeks', says Von Hugel--and he might have said 'in all classical thought'--'he who says immortal says god. The conceptions are interchangeable.' If men can go to heaven it is because they came from there; their ascent is a return. That is why the body is 'fetters'; we come into it by a sort of Fall. It is irrelevant to our nature; 'the mind of each man is the man'. All this belongs to a circle of ideas wholly different from the Christian doctrines of man's creation, fall, redemption, and resurrection. The attitude to the body which it involves was to be an unfortunate legacy for medieval Christendom.
Cicero also hands on a doctrine which may have helped, for centuries, to discourage geographical exploration. The Earth is (of course) spherical. It is divided into five zones, of which two, the Artic and the Antarctic, are uninhabitable through cold. Between the two habitable and temperate zones spreads the torrid zone, uninhabitable through heat. That is why the Antipodes, the 'contrariwise-footed' people who 'plant their footsteps in the direction opposite to you' (adversa vobis urgent vestigia), and live in the southern temperate zone, 'are nothing to us. We can never meet them; a belt of deadly heat is between us and them'.
~C.S. Lewis, The Discarded Image, "Selected Materials: The Classical Period", (1964)
*The dream of Scipio