The terms “modern state system” and “national state system” apply more accurately to the period after the French Revolution (1789) than to the political system of western Europe evolving in the general direction of modern states during the preceding centuries. During a period of about three centuries (roughly, from 1500 or before to 1750 or 1800), systems of political economy contributing to state development, from time to time and in various areas of Western Europe, had so much in common that they are frequently referred to by economists as the mercantile system or mercantilism. Each of the developing states needed precious metals to serve as reserves for war, to finance the king and his court, and to establish generalized money economies, central tax systems, and other national institutions. For this reason types of economic policy that developed in a number of states were designed to encourage an excess of merchandise exports, to be paid for in specie. This kind of policy was advocated, for example, by Thomas Mun and Sir Joseph Child, British economists of the early seventeenth century. Policy to achieve the foregoing ends took the form of complicated trade restrictive systems involving import tariffs, export bounties, and related regulations.