Chalkous

The chalkous (plural chalkoi) was the smallest common denomination of ancient Greek money, a low-value unit that came to be struck as a bronze coin. Its name comes from chalkos, the Greek word for copper and bronze. In Athens eight chalkoi made one obol, so 48 chalkoi made a drachm, although the ratio differed from one city to another.

The chalkous filled the gap between the smallest practical silver coin and the everyday cost of bread, oil or a ferry ride. Its spread marks the moment when Greek coins began to serve ordinary small purchases rather than only large payments.

As a unit, the chalkous sat at the bottom of the Greek system of account. Above it came the obol, then the Attic drachma of six obols, the mina of 100 drachms and the talent of 60 minae. Multiples of the chalkous were also struck, such as the dichalkon (two chalkoi) and larger bronzes worth several chalkoi. Outside Athens other divisions were used, and some systems counted twelve chalkoi to the obol, so the coin's value must always be read in its local context. Some later writers on weights and measures also divided the chalkous into still smaller units called lepta, a word familiar from the lepton of the New Testament.

The earliest Greek coinages were struck in electrum and silver, starting with the Lydian stater. To make small change, many cities struck remarkably small silver fractions, some weighing only a fraction of a gram and easy to lose. Bronze offered a practical alternative. Bronze small change appeared in Sicily and southern Italy in the fifth century BCE, and by the fourth century it had spread to Athens and most of the Greek world.

Athens experimented with emergency coins of silver-plated bronze late in the Peloponnesian War, when its silver supplies were cut off, but these were withdrawn afterwards. Regular Athenian bronze small change, including the chalkous, became established during the fourth century BCE.

A bronze chalkous was not worth its weight in metal at the stated value. It was a token coin, accepted because the issuing city stood behind it and would take it in payments, much like modern small change. In this respect the chalkous anticipated later fiat currency, whose value rests on the issuer rather than on metal content. The gap between face value and production cost gave cities a modest profit, a form of seigniorage.

The token nature also limited its range. Bronze generally circulated close to home and was rarely accepted as legal tender in other cities, where travellers had to change it into local coin or silver.

In the Hellenistic kingdoms bronze became more important still. The Seleucid coinage included plentiful royal and civic bronze, and Ptolemaic coinage in Egypt developed a system in which many prices were reckoned in bronze. As a medium of exchange for daily life, bronze small change was used far more often than the silver tetradrachm.

Under Roman rule, many Greek cities continued to strike their own bronze for local use, alongside Roman small change such as the as. The old Greek denomination names faded over time, but the principle the chalkous represented, low-value token coinage for everyday money use, has remained part of almost every currency system since.

• American Numismatic Society
• British Museum – Collection online