“Playing cards existed in China in or before the twelfth century, were introduced into Europe from China in the thirteenth century and were spread quickly from Europe over the civilized world. Certain Chinese cards which have come down to the present time were imitated from Chinese paper notes which bore pictorial symbols of their value. These pictures furnished the suit marks of the Chinese pack, and, copied again in Europe, without knowledge of their true significance, gave rise to the suits of coins, clubs, swords and cups of the eary European game.”

—Stewart Culin, quoted in A History of Playing Cards by Catherine Perry Hargrave, 1930.