The first gold coins to circulate in the British colonies, and later in America, were not coins struck in the United States. The first coins in circulation were Spanish gold coins struck in New World Mints from Mexico City, which arrived in the U.S. as the result of trade. Before American fought for its independence, the British starved the colonies of coinage in order to force Americans to barter raw materials for finished British manufactured goods As a result, merchants in the colonies became accustomed to using the Spanish Gold Escudo in its several denominations. When the Continental Congress composed standards for continental coinage, they followed the proposal, supported by Thomas Jefferson, to base the coinage standards on Spanish coins. Ultimately, this system gave the United States all of its circulating gold coin denominations. Many U.S. gold coin enthusiasts assemble these old Spanish gold coins, as they were legal tender in the United States until 1857. Gold coins struck during the time of the American Revolution are particularly favored, as it is possible they could have been carried in the pockets of America's Founding Fathers.