Western geographical knowledge of the East as American soldiers’ letters during the World War added to our geographical knowledge of France. MEDIEVAL CONCEPTION OF THE KNOWN WORLD The usual medieval conception of the known world was of a circular or oval area, divided into three continents. Asia occupied the eastern portion and was cut off from Europe by the Tanaïs (Don) and from Africa by the Nile. The Mediterranean, piercing the center of the western section, separated Europe from Africa. The relative size of the continents was variously represented; Asia was usually thought to be much larger than either Europe or Africa. The two latter were believed to be of about the same size. PARADISE One of the principal Biblical contributions to medieval geography was Paradise with its four rivers.[299] In the maps of the period, the garden is drawn at the easternmost limits of the world in accordance with the words of Genesis (ii, 8), “And the Lord God planted a garden eastward in Eden.”[300] Martianus Capella, however, by following a Greek tradition which placed the Hyperboreans in a favored and delightful country of the far north, caused certain of the Church Fathers to look northward for Paradise.[301] Modeling their account of Paradise on the Biblical description and on the ideal landscape of the Roman poets,[302] the men of the Middle Ages conceived of the garden as a deliciously cool and shady meadow, made beautiful with flowers of many sorts, watered by murmuring streams, and redolent with sweet odors.[303] Many theories were elaborated concerning the surroundings of the forbidden garden.[304] In order that men be kept out, an impassable barrier must have encircled it. Some believed that this was an immense wall; others, a ring of flames; others, mountains and deserts. Some placed Paradise on an island in the ocean; Cosmas removed it beyond the ocean to the shores of unknown lands in the east; Augustine, Origen, and Philo regarded it as allegorical and not real at all. RIVERS OF PARADISE