Trade, Coinage & the Roman Economy
How goods and money actually moved around a sea the Romans called their own.
The Mediterranean was, in the most literal sense, an internal Roman lake by 117 CE — mare nostrum, "our sea" — and the empire's economy ran on that fact. Grain grown in Egypt and North Africa fed Rome's roughly one million residents; wine and oil moved the other way from Italy, Spain, and Gaul; and luxury goods — silk from China, pepper from India, incense from Arabia — arrived through a relay of middlemen that started well outside Rome's own borders.
Coinage held the whole system together. The mint at Rome struck the gold aureus and silver denarius that circulated empire-wide, but running a currency at that scale from one city was impractical, so provincial mints struck their own coin under license — Antioch's silver tetradrachms paid the legions fighting Parthia, Alexandria ran a closed currency system that didn't circulate outside Egypt at all, and something like 120 smaller civic mints across Asia Minor and the Levant struck their own bronze small change for local use.
Shipping followed the seasons, not the calendar: the sailing season (mare apertum) ran roughly May to September, when Mediterranean weather was predictable enough to risk an open-water crossing; from November to March (mare clausum) most captains kept their ships in harbor. A grain convoy from Alexandria to Puteoli or Portus, sailing with the summer Etesian winds, made the return trip against them — Pliny the Younger complained that ships bound for Rome in the wrong season could take two months for a crossing that should take three weeks.
Below: the empire's mints, and a sample of the specific trade routes already mapped — the Amber Road down from the Baltic, the Silk Road's Roman leg out of Antioch and Palmyra, the grain lanes that fed Rome itself.
- Rome · gold, silver, bronze
- Lyon · none (dormant since the Flavian period)
- Antioch · silver, bronze
- Alexandria · billon, bronze
- Caesarea · bronze
- Kayseri · silver
- Izmit · bronze
- Pergamon · silver, bronze
- Ephesus · silver, bronze
- Smyrna · bronze
- Sardis · bronze
- Tarsus · silver, bronze
- Iznik · bronze
- Apamea Cibotus · bronze
- Laodicea on the Lycus · bronze
- Tripoli · bronze
- Tyre · silver, bronze
- Sidon · bronze
- Beirut · bronze
- Ashkelon · bronze
Sources
- Roman Imperial Coinage (RIC), vol. II (Trajan)
- Pliny the Younger, Letters
- Public data: public/data/mints.geojson, public/data/trade_routes.geojson
- CAH XI, The High Empire, 70–192 CE (Cambridge Ancient History, 2nd ed.)
- Fergus Millar, The Roman Near East, 31 BC–AD 337
- Barrington Atlas of the Greek and Roman World
More to read
Roman Maps shows the empire frozen at 11 August 117 CE, the day Trajan died — its moment of greatest territorial extent. Explore the full map →