In international economics, the balance of payments (also known as balance of international payments and abbreviated BOP or BoP) of a country is the difference between all money flowing into the country in a particular period of time (e.g., a quarter or a year) and the outflow of money to the rest of the world. These financial transactions are made by individuals, firms and government bodies to compare receipts and payments arising out of trade of goods and services. The balance of payments consists of two components: the current account and the capital account. The current account reflects a country's net income, while the capital account reflects the net change in ownership of national assets. History Until the early 19th century, international trade was heavily regulated and accounted for a relatively small portion compared with national output. In the Middle Ages, European trade was typically regulated at municipal level in the interests of security for local industry and for established merchants. (Annual fairs would sometimes allow exceptions to the standard regulations.) Mercantilism Beginning in the 16th century, mercantilism became the dominant economic theory influencing European rulers. Local trade regulations were replaced by national rules aiming to harness the countries' economic output. Measures to promote a trade surplus (such as tariffs) were generally favored. The prevailing orthodoxy of the mercantilist age was the (now discredited) notion that the accumulation of foreign exchange or, at that time, precious metals, made countries wealthier, and so countries favored exporting their own goods to run balance of payments surpluses. This viewpoint prevails in England's Treasure by Foreign Trade (1664) by Thomas Mun. Economic growth remained at low levels in the mercantilist era; average global per capita income is not considered to have significantly risen in the whole 800 years leading up to 1820, and is estimated to have increased on average by less than 0.1% per year between 1700 and 1820. With very low levels of financial integration between nations and with international trade generally making up a low proportion of individual nations' GDP, BOP crises were very rare. 1820–1914: Classical economics The mercantilist dogma was attacked first by David Hume, then Adam Smith and David Ricardo. In the essays Of Money and Of the Balance of Trade, Hume argued that the accumulation of precious metals would create monetary inflation without any real effect on interest rates. It is the foundation of what is known