The Greek city states clustered about the shores of the Mediterranean like ‘frogs on a pond’, as Plato put it (Phd. 109b). And the centres of greatest economic importance – not only Greek but Phoenician as well – were by and large seaports: Tyre, Miletus, Byzantium, Athens and its Piraeus, Syracuse, Carthage, Marseilles. There was good reason for this. The shortest and least arduous way of getting from one distant point to another was most often by the body of water that lay so conveniently at the centre of the Greek and Roman world. Men learned to sail on it as early as the eleventh millennium B.C. and were doing so regularly by the seventh (CAH 1.1, 570–1).

COMMUNICATIONS BY LAND

Travel by sea, to be sure, had its disadvantages, as we will note in a moment, but they were far less grave than those by land. There the very possibility of movement depended squarely upon the existence of roads, and its speed on the nature of the terrain. In the flat plains of southern Mesopotamia, by the second millennium B.C., there were roads between the major city states, like those from Nippur to Ur or from Babylon to Larsa, and the international route that ran from Egypt north along the Levantine coast to Beirut dates back at least to the late second. Minoan Crete had roads between its important points, and so did Mycenaean Greece. The Assyrian empire, in the years of its greatness, c. 900–600 B.C., maintained an efficient government dispatch service and the network of roads that this required; both were taken over and improved by the Persians.