The use of money dates back some 4,000 years, when people began using something of recognized value, such as precious metals including gold and silver, to purchase goods and services. In the absence of money, all transactions were made on the barter system, which is an exchange of goods and services negotiated by the parties involved. The introduction of money simplified the acquisition of products and services. The ancient country of Lydia, in the western part of Asia Minor (modern-day Turkey), is credited with the first use of standardized coins, made of gold and silver, in the seventh century B.C.