At first the inhabitants of any single town would regard those of all others as their enemies, but after a time they would find it convenient to exchange some of their superfluities for those of their neighbours, and in this way trade would begin. Markets would become neutral ground, in which mutual animosities would be, for a time, laid aside for the common advantage; and it would often happen that localities on the border line of two states would be chosen as places for the exchange of goods, ultimately giving rise to the existence of a fresh town. As commercial intercourse increased, the very inaccessibility of fortress towns on the heights would cause them to be neglected for settlements in the valleys or by the river sides, and, as a rule, roads pick out valleys or level ground for their natural course. For military purposes, however, it would sometimes be necessary to depart from the valley routes, and, as we shall see, the Roman roads paid no regard to these requirements. The earliest communication between nations, as we have seen, was that of the Phoenicians by sea. They founded factories, or neutral grounds for trade, at appropriate spots all along the Mediterranean coasts, and the Greeks soon followed their example in the Ægean and Black Seas. But at an early date, as we know from the Bible, caravan routes were established between Egypt, Syria, and Mesopotamia, and later on these were extended into Farther Asia. But in Europe the great road-builders were the Romans. Rome owed its importance in the ancient world to its central position, at first in Italy, and then in the whole of the Mediterranean. It combined almost all the advantages necessary for a town: it was in the bend of a river, yet accessible from the sea; its natural hills made it easily defensible, as Hannibal found to his cost; while its central position in the Latian Plain made it the natural resort of all the Latin traders. The Romans soon found it necessary to utilise their central position by rendering themselves accessible to the rest of Italy, and they commenced building those marvellous roads, which in most cases have remained, owing to their solid construction. "Building" is the proper word to use, for a Roman road is really a broad wall built in a deep ditch so as to come up above the level of the surface. Scarcely any amount of traffic could wear this solid substructure away, and to this day throughout Europe traces can be found of the Roman roads built nearly two thousand years ago. As the Roman Empire extended, these roads formed one of the chief means by which the lords of the world were enabled to preserve their conquests. By placing a legion in a central spot, where many of these roads converged, they were enabled to strike quickly in any direction and overawe the country. Stations were naturally built along these roads, and to the present day many of the chief highways of Europe follow the course of the old Roman roads. Our