Comment by IAmBroom

> For most of human history the money was stable.

Wildly inaccurate, thanks to forgery and coin shaving - sometimes even governments officially reduced the silver or gold content to make more money out of their coin reserves. Even when proto-banks began issuing letters of credit, the quasi-fiat letters were subject to loss of confidence.

However, the availability and quasi-fungibility of other silver/gold currencies meant that if you didn't trust Edward's penny, you could use a Dutch penning instead. That provided an alternate path to dampen inflation, as long as the dominant currency was coinage.

But it was equally hard to buy a pig or a new suit with silver pennies by the 20th century. Bank notes, even when theoretically backed by exchange for their value in precious metals (the Gold Standard), were even easier to forge, and suffered from "loss of faith" inflation (runs on banks meaning they couldn't practically be exchanged for 14 pounds of silver pennies).