While fiat currencies might have been used locally when gold wasn't available, gold was the world currency until the 70's. https://en.wikipedia.org/wiki/Nixon_Shock https://en.wikipedia.org/wiki/Nixon_Shock
And even that only from about the 1820s or 1870s to the 1970s. The gold standard was only introduced because Europe ran out of silver after using it all to pay for Chinese goods.