What Prevailing economic theory of the late 18th century was?

The prevailing economic theory of the late 18th century was mercantilism, which emphasized the importance of a nation’s wealth as measured by its stock of precious metals, primarily gold and silver. Mercantilists believed that a country should export more than it imported to achieve a favorable balance of trade, thus accumulating wealth. This theory supported strong government intervention in the economy to regulate trade and promote national interests. It laid the groundwork for later economic theories, including classical economics and free-market principles.