Ptolemaic Coinage

Ptolemaic coinage was the money issued by the Ptolemaic dynasty, the Macedonian royal house that ruled Egypt from the death of Alexander the Great until Cleopatra VII and the Roman conquest in 30 BCE. It is known for three features that set it apart from other Hellenistic coinages: a reduced silver weight standard, a closed currency system inside Egypt, and an unusually heavy reliance on bronze.

Ptolemaic coins were struck mainly at Alexandria, but also in possessions such as Cyprus, Cyrenaica and, until around 200 BCE, the Phoenician coast. Their long-lived design, with the portrait of the dynasty's founder on silver for nearly three centuries, makes them among the most recognisable ancient coins.

Ptolemy, one of Alexander's generals, took charge of Egypt as satrap in 323 BCE. His first silver kept Alexander's designs and weight, the same standard as the Attic drachma. He soon introduced a striking new image of the dead Alexander wearing an elephant-scalp headdress. After Ptolemy declared himself king around 305 BCE, his own portrait appeared on the front of the tetradrachm, with an eagle standing on a thunderbolt on the back and a legend naming "King Ptolemy". His successors kept this portrait and reverse on their silver, so the founder's face remained on Egyptian silver for generations.

Between roughly 310 and 290 BCE, the Ptolemaic tetradrachm was reduced in stages from about 17 grams to about 14 grams. The new weight was close to the standard already used in Phoenicia. Because Ptolemaic silver was lighter than Attic-standard coin circulating elsewhere, foreign coins brought into Egypt contained more silver than the local coins issued in exchange. Reminting them produced a profit for the crown, a clear early example of seigniorage.

Inside Egypt, only royal coinage was accepted as legal tender. Merchants and travellers arriving with foreign money had to change it at royal banks and exchange offices, much as a modern state with limited currency convertibility controls who may hold foreign money. The obligation resembles later rules on foreign exchange surrender. Papyri from the mid-third century BCE, including the archive of the estate manager Zenon, record foreign coin being handed in for reminting and the practical difficulties this caused.

The system let the crown control the money supply, collect taxes in its own coin and earn fees on every currency exchange. It also helped spread coined money deep into an economy where many payments had long been made in grain or other goods.

The Ptolemies struck substantial gold coinage. Under Ptolemy II, large gold octadrachms honouring his sister-wife Arsinoe II were issued; such coins are often identified with the mnaieion, a piece worth a mina, or 100 silver drachms. Gold was mainly used for large payments and royal gifts.

Bronze was central to everyday life. The Ptolemaic mints produced large bronze coins, typically with the head of Zeus Ammon and an eagle, in a range of sizes far beyond the small change, such as the chalkous, found in most Greek cities. From the late third century BCE many prices and accounts in Egypt were reckoned in bronze drachms, so bronze served as a practical unit of account alongside silver.

In the second and first centuries BCE the silver content of the tetradrachm fell, and by the reign of Cleopatra VII the coin was heavily alloyed with base metal. This currency debasement reflected dynastic conflict, war costs and payments to Rome. Cleopatra's bronze coins carried marks of value, generally read as 80 and 40 drachms, showing how far bronze reckoning had moved from the original silver standard.

When Octavian annexed Egypt in 30 BCE, Rome kept the closed system. Alexandria went on striking its own billon tetradrachms for local use, separate from the Roman denarius, until the coinage reforms of the late third century CE. Rival kingdoms took a different path: Seleucid coinage stayed largely on the heavier Attic weight, although the Phoenician mints it took from the Ptolemies kept the lighter standard.

• Ptolemaic Coins Online – American Numismatic Society
• British Museum – Collection online