The American Dollar’s history dates back to before the United States of America declared their independence from British rule.
In 1900, United States Government moved to Gold Standard. This meant that all currency used in the nation was backed up by a specific amount of gold held at the Federal Repository. The value of a dollar at that time was equal to 23.22 grains gold.
The Gold Standard was repeatedly suspended and then reinstated in the following years. In 1963, the United States followed most other countries of the world by making their currency a fiat money, which is not directly backed up by gold or any other precious metals.