William Bramley/The Gods of Eden/21/218/3

By the 17th century, the Medici banking house of Italy had come up with the idea of using gold as the commodity upon which to base all paper currency. Gold was touted as the perfect basis for paper notes because of the scarcity and desirability of gold. This was the beginning of the "gold standard" in which all other goods and services are valued in relation to gold (and sometimes silver). The gold standard was certainly a terrific idea for those people who owned plenty of gold and silver, but it created an artificial reliance on a commodity that is not nearly as useful as many other products. To base an entire monetary system on a single commodity is better than basing it upon no commodities at all, but even under a gold standard paper notes will far exceed the metals used to back the notes. The best solution is to root a money supply firmly in a nation's entire valuable output so that the money acts as an accurate reflection of that output.