People have traded different currencies for thousands of years. Traders used the best technology available, such as carefully designed boats, to travel and buy and sell goods in foreign markets.
Globalisation increased in the twentieth century, and multinational corporations became common. As technology developed, more people began to travel and do business worldwide. People also began to holiday abroad in far greater numbers. These changes meant that currency exchange became far more common.
The amount of another currency that you can buy with your money is known as the exchange rate. This exchange rate varies depending on several factors.