into dozens of petty states, if Spain and Gaul could attract traders when all land and sea routes were dangerous, why should the union of these lands with many others produce a depression instead of a boom?
In the first place, the political institutions of the Empire were out of step with its economic institutions. Politically, the Mediterranean basin had been united in a highly centralized state; economically it was still divided into a number of almost self-sufficient regions. The Empire had to support a large bureaucracy, and an even larger army; it had to defend the almost impossibly long frontiers which enclosed the Mediterranean world. The cost of the imperial government was not great by our standards, but it seemed very high to men of the fourth century A.D. The total population of the Empire was much less than that of the same regions today, which meant that each individual had to carry a larger share of the burdens of government.
Even worse, the chief occupation of the inhabitants of the Empire was agriculture, so that wealth per capita was very low. The Romans despised commerce, which remained largely in the hands of Syrians and other peoples of the Levant. This gave the eastern half of the Empire certain advantages over the West, but even in the East commerce added less to the wealth of the Empire than might have been expected. Trade in oriental luxury goods formed a large part of the stream of Roman commerce and Rome had little to offer India, Persia, and China in return for imports of silks, spices, perfumes, and precious stones. A steady stream of gold and silver flowed from the Empire to the Orient, leaving the Mediterranean world short of specie. The absence of any well-developed credit system made it impossible to replace the precious metals with paper, and the resulting disorganization of the currency made it difficult to do business of any kind. Active internal trade would have eased these monetary problems, but internal trade seems to have declined in the last centuries of the Empire. All the Mediterranean lands produced the same agricultural staples — wheat, olive