"Metallic siege money of Leyden [was] struck in 1574 from a round coin die onto a diamond shaped silver planchet. As the supply of silver available for coinage dried up during the siege, Leyden continued to mint coins made from paper torn from prayer books. These cardboard 'notes' became the first paper money to appear in the Western world. Prior to this only the Chinese used paper money."

from "Siege Notes" by John E. Sandrock

"The latest use of leather for regal currency in Europe appears to be that of Russia. From about the eighth century onwards, as the commerce of that country expanded, and the supply of hides for exchange or barter purposes failed to keep pace with the monetary requirements of the people, the use of whole skins was discontinued, and skin snouts, ears and claws were substituted. These, in turn, gave place to pieces of skin or leather, which at first were of irregular shape about an inch square in size, but were afterwards issued in a circular form, and impressed with the government stamp. They continued in use until the reform of the currency in the latter part of the reign of Peter the Great, who died in 1725."

from "Leather Currency" by William Charlton