Mercantilism is an economic theory that emphasizes the accumulation of wealth through trade and the balance of trade surplus. It emerged during the 16th to 18th centuries and emphasized government control over trade, colonies, and currency. Mercantilism aimed to increase a nation's wealth and power by exporting more than importing, accumulating gold and silver, and maintaining a strong military. Today, Mercantilism is seen as outdated but its principles still influence modern trade policies.