Some collectors may already have come across them: small round capsules in which real stamps are visible, which were in circulation in several European countries during and after World War I as a substitute for small change. However, the origins of this form of currency goes back a long way, to the American Civil War, which began in April 1861 after conflicts intensified between the northern states of the Union and the southern states of the Confederacy.
As hopes of an early end to the War of Secession faded due to a series of Union defeats, panic spread through the financial markets. The value of banknotes against hard money began to fall dramatically. As a result of speculation and hoarding, all forms of coins disappeared from circulation, whether made of silver, gold or even copper-nickel.