Mercantilism meant a strict control of trade by the metropolis. Colonies were not free to trade with other nations. The idea of a controlled market was based on the idea that a nation should try to remain completely autonomous, particularly in the production of food and other basic goods. Under this idea, allowing free trade would weaken the nation's ability to provide food and grain to its population in a time of need.
Mercantilism also meant that the ruler had a responsibility with all his subjects in regards to his ability to secure food and basic goods in a protected market. Producers, particularly those in the colonies felt that this limited their margin of profit and excluded them from more lucrative offers.
