Persistent Misconceptions. The area around the Mediterranean Sea was already well explored by Homer's time. Nevertheless, misconceptions about the region continued throughout antiquity. Hipparchus, for example, believed that it flowed directly into the Red Sea. Eratosthenes held the notion that the Mediterranean Sea covered one-half of the inhabitable world, of which the Pillars of Heracles (Gibraltar) were the westernmost point. Strabo, writing in the first century C.E., divides the earth's waters into two major bodies (which include the various lakes and seas throughout the world): the Interior Ocean (Mediterranean) and the Exterior Ocean (flowing from the Caspian Sea into the proverbial Northern Ocean).

Climatology. Despite these ongoing misconceptions, knowledge of the Mediterranean basin was fairly detailed by the first century C.E. Strabo knows the rivers of Spain and cites the Guadalquiver and the Ebro flowing into the Mediterranean. Strabo also speaks in...