In A.D. 1944, an international conference was held at Bretton Woods, New Hampshire, to establish a new monetary system for the post-WWII world. A fundamental principle of the resulting “Bretton Woods Agreement” was that the US dollar would be backed by gold and would come to be used as the world reserve currency.
In A.D. 1971, President Nixon closed the “gold window” and stopped redeeming foreign-held US dollars with gold. Some people suppose that when the US dollar became pure fiat and was no longer redeemable in gold, the Bretton Woods Agreement ended.
However, the original Bretton Woods Agreement involved much more than merely promising to redeem foreign-held dollars with gold. Vestiges of that Agreement continue to function and exert influence under the oversight of The Bretton Woods Committee.