Roman Tetradrachm of Egypt

The most intriguing aspect of the Roman Tetradrachm from Egypt is how it stubbornly clung to an outdated weight standard, the Alexandrian tetradrachm, even as the rest of the Roman Empire shifted to the denarius system around the mid-3rd century. This coin, struck in billon—a silver alloy diluted with copper—served as the backbone of Egypt's economy under Roman rule, from 30 BC when Octavian annexed the province.

Design-wise, these pieces typically bore the emperor's profile on the obverse, often with a radiate crown for later issues, and an eagle or a god like Zeus on the reverse. The Alexandria mint produced them in vast quantities, though exact figures vanished with ancient records. Variations in metal purity reflected economic strain; by the 270s AD, the silver content had plummeted.

One dry note: Historians debate if these coins funded Cleopatra's escapades or just the empire's bureaucracy—probably the latter.