In the long period from 1500 to 1800, western European nation-states were all influenced by a set of ideas. known as mercantilism. (111) Mercantilist doctrine and institutions were important because they were held by practical businesspeople and heads of stare who strongly influenced public policy and institutional change.The primary aim of mercantilists was to achieve power and wealth for the state. To generate an inflow of gold or silver through trade, the value of exports should exceed the value of imports. And the state could attain great power only if political and economic unity became a fact. (112) If all the materials necessary to foster domestic industry were not available they could best be obtained by establishing colonies or friendly foreign trading posts from which such goods could be imported. And a strong merchant marine could carry foreign goods, thereby helping to secure favorable trade balances. (113) Mercantilists believed that these means of achieving national power could be made effective by the passage and strict enforcement of legislation regulating economic life.(114) Almost as soon as Virginia tobacco began to be shipped in commercial quantities to England, King James I levied a tax on it while agreeing to prohibit the growth of competing tobacco in England. Taxes, regulation, and subsidies were all used as mercantile policies, but the primary ones that affected the colonies were the Navigation Acts.In 1640s, Americans had slipped into the habit of shipping their goods directly to continental ports, and the Dutch made great inroads into the carrying trade of the colonies. After the Restoration, England was in a position to enforce a strict commercial policy, beginning with the Navigation Acts of 1660 and 1663. Despite the continued modifications to these acts by policy changes, it is sufficient to note three primary categories of trade restriction:(115) All trade of the colonies was to be carried in vessels that were English built and owned, commanded by an English captain, and manned by a crew of whom three-quarters were English.All foreign merchants were excluded from dealing directly in the commerce of the English colonies. They could engage in colonial trade only through England and merchants resident there.Certain commodities produced in the colonies could be exported only to England (essentially any destination within the Empire). These 'enumerated' goods included sugar, tobacco, cotton, indigo, ginger and so on.(81)