<P> Piggy bank (sometimes penny bank or money box) is the traditional name of a coin container normally used by children . The piggy bank is known to collectors as a "still bank" as opposed to the "mechanical banks" popular in the early 20th century . These items are also often used by companies for promotional purposes . The use of the name' piggy bank' gave rise to its widely recognized' pig' shape, and many financial services companies use piggy banks as logos for their savings products . </P> <P> Piggy banks are usually made of ceramic or porcelain . They are generally painted and serve as a pedagogical device to teach the rudiments of thrift and savings to children; money can be easily inserted . Many piggy banks have a rubber plug located on the underside; others are made of vinyl and have a removable nose for easy coin access . Some incorporate electronic systems which calculate the amount of money deposited . Some piggy banks do not have an opening besides the slot for inserting coins, which will lead to smashing the piggy bank with a hammer or by other means, to obtain the money within . </P> <P> Pygg is an orange colored clay commonly used during the Middle Ages as a cheap material for pots to store money, called pygg pots or pygg jars . There is dispute as to whether "pygg" was simply a dialectal variant of "pig ." By the 18th century, the term "pig jar" had evolved to "pig bank". As earthenware was supplanted by other materials, such as glass, plaster, and plastic, the name gradually began to refer specifically to the shape of the bank, instead of what was used to make it . </P> <P> The oldest Western find of a money box dates from 2nd century BC Greek colony Priene, Asia Minor, and features the shape of a miniature Greek temple with a slit in the pediment . Money boxes of various forms were also excavated in Pompeii and Herculaneum, and appear quite frequently on late ancient provincial sites, particularly in Roman Britain and along the Rhine . </P>

Where did the idea of a piggy bank come from