In fact, the cost of transacting are the key to the performance of economics. There have always been gains from trade, as classical international trade theory has taught, but so too have there been obstacles to realizing these gains. If transport costs were the only obstacle, than we would observe through history an inverse relationship between transport costs, on the one hand, and trade and exchange and the well-begin of societies on the other. But recall that as early as the Roman Empire of the first two centuries AD trade was possible over a vast area, even with the transport costs of the time; and that after the end of the Roman Empire trade declined and probably the well-begin of societies and individual groups declined as well. It was not that transport costs had risen; but that the costs of transacting had risen as regions expanded, and unified political system that could effectively enforce rules and laws disappeared.