The modern world, with its common fund of culture and its community of interests uniting different peoples, could arise from these conditions only after long centuries of struggle. The unity of the Christian faith was needed to confirm the union of peoples in a common civilization. The process of union begins, however, at the point which we have reached; the great conquests of Alexander of Macedon, and those of Rome, did much to break down the barriers between peoples, and to prepare them for the acceptance of a common civilization and a common religion. It is to be hoped that the student knows already something of the narrative of those conquests. We shall have to confine ourselves to the results as they appear in the history of commerce. Here the reader can merely be reminded that Alexander united the eastern world into an empire extending from Greece to India, a little before 300 B.C., and that the Romans began about 200 B.C. to extend their authority outside the Italian peninsula, and before the birth of Christ had subjected to it practically all the peoples whose history we have been studying. =21. Effect of Alexander’s conquests on commerce; decline of Greece.=—In appearance the empire of Alexander outlived its founder but a few years, and then dissolved. Alexander, however, was a civilizer as well as a conqueror; he endowed the East with a common fund of Greek culture; and however distinct or hostile the states might seem thereafter the peoples were united as they had never been before. Commerce took on a new aspect. Greece, which before had been at the center of the great commercial movements, was now left on the western edge. Greek merchants could for a time use their former commanding position to share in the great commercial development, but in the long run their struggle was hopeless. The most energetic Greeks left their home to settle in eastern countries which were richer, more populous, and closer to the great currents of trade. Corinth was the only city which managed to maintain and extend its trade. Athens declined rapidly in commercial importance; and grass grew and cows were pastured in the streets of other towns which had once been important markets.