How to identify an old Roman coin in five steps
Identifying a Roman coin is mostly a process of elimination. You look at the metal and size, then the portrait, the inscription (the legend), and the reverse design, and each clue narrows the field. You do not need to read Latin fluently; a handful of recurring abbreviations carry you a long way.
- Note the metal, weight and diameter.
- Look at the portrait and headgear on the obverse (front).
- Read the legend around the edge.
- Study the reverse design and any letters in the field or exergue.
- Match your findings against a catalog or database.
Photograph both sides before you start, and avoid cleaning the coin. Cleaning generally lowers value and can erase the very details you need.
Step 1: Metal, weight and size
Start with what the coin is made of. Roman coins fall into broad groups: gold, silver, and base metals such as bronze, brass and copper. Bronze coins are often green, brown or black from age. Silver coins may look gray or dark. Late “silver” coins often contain a lot of base metal.
Weigh the coin on a small scale (grams to two decimal places) and measure its diameter in millimeters. A rough comparison with typical sizes helps point to a denomination, though wear, clipping and corrosion mean the numbers are only a guide.
Step 2: The obverse portrait
The front of most imperial coins shows a portrait of the emperor, an empress or a family member. Headgear is a quick clue:
- A laurel wreath is common across many periods and denominations.
- A radiate crown (spikes like sun rays) is typical of coins valued at more than the basic unit, such as the antoninianus, and of some bronze issues.
- A diadem (a band, sometimes jeweled) is common on later imperial coins.
- A bare head appears on some issues, especially early ones.
You can often get a rough date from portrait style. Hairstyles, beards and facial structure changed over the centuries, and emperors from Hadrian onward are commonly shown with beards. These clues are best treated as pointers to confirm with the legend.
Step 3: Reading the legend
The legend is the inscription around the portrait. It usually names the emperor and lists titles, and it is often abbreviated. Common elements include:
- IMP (Imperator, commander)
- CAES or CAESAR (Caesar)
- AVG (Augustus)
- P M (Pontifex Maximus, chief priest)
- TR P (Tribunicia Potestas, tribunician power)
- COS (Consul), often followed by a numeral
- P P (Pater Patriae, father of the country)
- DIVVS or DIVO (deified)
Some Latin spellings use V for the letter U, so you will see AVGVSTVS rather than AUGUSTUS. Worn coins may show only a few letters. Even two or three legible characters, together with the portrait, can identify the emperor. Titles with numbers, such as “TR P XII,” can help date a coin within a reign, though you will need a reference list for the exact years.
Step 4: The reverse and the mint mark
The reverse shows a deity, a personification such as Pax (peace) or Victoria (victory), a military scene, a building or an emblem. The reverse often carries a slogan or caption. Many types are catalogued by these captions.
On many later coins, letters at the bottom (the exergue) indicate the mint city, often an abbreviation like ROM for Rome, ANT for Antioch or similar. Single letters or symbols in the field can indicate the workshop within a mint. Mint marks are usually found on third and fourth century coins; earlier coins often have none.
Common Roman denominations
If you are asking “what are Roman coins called?”, these are the names collectors meet most often. Exact values and weights changed over time, so treat this as a general overview.
| Denomination | Metal | Notes |
|---|---|---|
| Aureus | Gold | High-value coin of the early and middle empire |
| Denarius | Silver | The standard silver coin for much of the republic and early empire |
| Antoninianus | Silver, later heavily debased | Introduced in the early third century, shown with a radiate crown |
| Sestertius | Brass | Large coin, popular with collectors for its big portraits |
| Dupondius and As | Brass and copper | Smaller bronze denominations |
| Follis | Bronze | Associated with late Roman reforms |
| Nummus | Small bronze | Very common late Roman coin |
The Roman system changed repeatedly, so a coin’s name depends heavily on its period. The coins familiar from the Gospels are discussed in our article on Roman coins from the time of Jesus.
Step 5: Matching your coin to a catalog
Once you have an emperor and a reverse type, search a reference. Widely used resources include:
- Online Coins of the Roman Empire (OCRE), a free online database from the American Numismatic Society that lets you filter by emperor, denomination, mint and reverse description.
- Roman Imperial Coinage (RIC), the standard multivolume catalog, which provides the reference numbers dealers cite.
- Auction archives and dealer sites that list reference numbers alongside images.
The Portable Antiquities Scheme database also lists many Roman finds from England and Wales, which is useful if you are comparing against similar finds.
What if my coin is too worn or corroded?
Many field finds, especially bronzes, are very worn. Focus on whatever survives: the rough size, the headgear, the pose on the reverse, and any partial letters. Compare with images of known coins of similar size. If it still resists identification, consider asking a local museum, a numismatic society, or an experienced dealer. In the UK, a Finds Liaison Officer can help; see our guide to identifying Roman coins found in the UK.
Is my old Roman coin worth anything?
Most Roman coins found by hobbyists are common types in low grade and are worth modest amounts. Value tends to rise with:
- Condition and sharpness of the portrait and legend
- Rarity of the emperor or reverse type
- Metal, since gold generally commands more than silver or bronze
- Eye appeal, including centering and attractive toning or patina
Counterfeits and modern copies exist, so if you plan to buy or sell a valuable piece, seek an opinion from a reputable specialist or grading service. And yes, you can buy genuine old Roman coins from established dealers and auction houses at a wide range of prices, with common late Roman bronzes among the cheapest.