The Roman Empire 2 of 5 Currency devaluation
Nero devised a way to artificially increase the number of coins to keep up with the expanding government spending. Nero tampered with the coinage by decreasing the silver and gold content of its coins. Reducing the content to as much as 85% increased the monetary base as it allowed more extra coins to be minted as a result of this reduction. A pound of silver that produced 84 Denarii can now be stretched up to 96 pieces of Denarii. Later emperors followed this public deception that allowed them to increase the number of coins to pay for their ballooning government spending.
http://history.econtrader.com/devaluation_of_the_roman_currency.htm
He wasn't the only one. Some emperor after him plated copper coins with silver. He was a heavy drinker and when the silver plate wore off the high spots on the coin like his nose, the standing joke was that the coin more accurately portrayed him as his nose became copper red.
Things got so bad after a while that the citizens were forced to pay in real silver and gold, but the govt paid out in the debased coinage.
[Sidebar] Ever wonder why the dimes and higher coins have reeded edges? That was instituted to prevent "shaving" a sliver off the coin. Do it to enough of 'em and you had a weeks/months pay. Useless now with the clad coins.
When I sold some British sovereigns during the runup in the late '70s, the dealer said I had some unusually nice coins (not pockmarked). It seems that when sovereigns were the coin of the realm, the money boys would get a sackful and shake the daylights out of the bag. Then they would dump the coins and "pan" the cloth bag for the "dust".