How to identify a Roman coin: obverse, reverse, legend, mint
By Sébastien · · 7 min read
A Roman coin already tells you a lot when you hold it: a portrait, an inscription, a reverse scene, sometimes letters in the exergue. Reading them in order lets you move from an anonymous piece to a solid attribution. This article is part of the guide cataloguing an ancient coin collection.
The anatomy of a coin
A few terms come up constantly and structure any identification:
- Obverse: the main side, most often the emperor's portrait.
- Reverse: the other side, usually a deity, a personification or a scene.
- Legend: the inscription running around the edge, read clockwise.
- Exergue: the band beneath the reverse scene, often bearing the mint mark or an abbreviation.
- Mint and officina: the place of striking and the specific workshop, shown by letters.
1. Reading the obverse legend
The obverse legend names the figure and lists their titles: the emperor's name followed by abbreviations such as AVG (Augustus), CAES (Caesar), PF (Pius Felix), TRP (tribunician power), COS (consulship). These titles — especially the consulship or tribunician-power numbers — help date the striking to within a few years.
2. Observing the portrait
The portrait style, the beard, the hairstyle, the crown (laureate, radiate) point to an emperor or a period. A radiate crown on a bronze, for instance, often signals a double sestertius or an antoninianus. The portrait complements the legend: the two confirm each other.
3. Decoding the reverse
The reverse carries the political message of the issue: a deity (Jupiter, Mars, Victory), a personification (Pax, Salus, Concordia), a military or dynastic scene. Its legend describes the subject and often points to a precise catalogue type. It is a major attribution criterion.
4. Spotting the mint mark and the exergue
In the exergue and the field, letters indicate the mint (e.g. R for Rome, LUG for Lyon, SIS for Siscia) and the officina. These marks, highly codified under the Later Empire, are essential to distinguish two otherwise identical strikings.
5. Confirming with metal and module
The metal (gold, silver, bronze, billon) and the module (diameter, weight) confirm the denomination and rule out confusion. An aureus, a denarius and an antoninianus do not weigh the same; weighing and measuring are part of identification. Record these values in the file.
Completing the attribution
Once the piece is read, it remains to give it a catalogue number: see understanding RIC, RPC references and the OCRE database. And to store that identification for the long run, see the pillar cataloguing an ancient coin collection.
In practice with AncientDesk
AncientDesk lets you record legend, portrait, reverse, mint and metrology in a structured file, then search by any of these criteria — offline, locally. Unsure about a reading? Feel free to contact us.
Frequently asked questions
Where should I start to identify a Roman coin?
With the obverse legend, which gives the figure's name and titles, then the portrait. The reverse and its legend specify the type, and the mint mark refines the attribution. Metal and module confirm the denomination.
What do AVG, COS, TRP mean on a coin?
They are imperial titles: AVG for Augustus, COS for the consulship, TRP for the tribunician power. The associated numbers (COS III, TRP IIII) often allow dating the striking to within a few years.
Is the mint mark important?
Yes, especially under the Later Empire: the letters in the exergue indicate the mint and officina and distinguish otherwise identical strikings. They are essential for a precise attribution via RIC.
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