Having just finished a leisurely read of Michael Grant’s From Alexander to Cleopatra – The Hellenistic World, I now know something most people probably already know – that it was in the Hellenistic period that realistic portraiture developed and that this realism extended to coins. Furthermore, the successors of Alexander were the first to use portraits of the kings on their coins. My son says this wasn’t just in the Greek world.
Google Books’ preview of Graham Shipley’s The Greek World After Alexander, 323-30 B.C. says that Lysimachus, one of Alexander’s Successors, first put the face of Alexander on coins. I am not sure if this is true without qualification or whether earlier coins (from Alexander’s lifetime) showed Hercules or other gods with the facial characteristics of Alexander. Shipley says it was Ptolemy who first went further than using the face of the almost-divine Alexander by using his own visage. Shipley also says that when Hellenistic kings used their faces on coins, they used their faces on the obverse and Alexander on the reverse.
Alexander gave stature to the coins, so his face was used for two centuries. Although the Ptolemies reduced the content of the standard for the silver drachma to 14.3 g, by 290, the Attic 17.2 g was the standard elsewhere.