Mercantilism was an economic doctrine prominent in Europe between the 16th-18th centuries that advocated for government control over foreign trade to ensure national prosperity and security. It promoted a positive trade balance and led to colonial expansion and frequent European wars. While criticized by Adam Smith and others, it remained influential into the 19th century. Mercantilist policies included tariffs, trade monopolies, export subsidies, and limiting imports. Barter is a method of exchanging goods without money that still exists today, especially during economic crises, and includes corporate and internet-based varieties.