This document provides a history of currencies and exchange rates. It discusses how barter systems led to the development of coins and currency to serve as a medium of exchange. Currencies were originally tied to gold through the gold standard from 1821 to 1914. However, most countries moved to a floating exchange rate system after World War II. The key factors that determine exchange rates between currencies today include differences in inflation rates, interest rates, current account balances, public debt levels, trade terms, and political/economic conditions.