Fiat money derives its value from government regulation rather than being backed by a commodity like gold. It originated in 11th century China and its use became widespread during later Chinese dynasties. Marco Polo observed that paper money issued by Kublai Khan was readily accepted as a medium of exchange throughout his empire. Some of the earliest forms of fiat currency outside of China included "bills of credit" issued by American colonies to pay obligations and provincial taxes. After World War I, many governments suspended redeeming currency for gold or silver, leading to hyperinflation in some countries from excessive money printing without responsibility for economic consequences.