BidArch research guide
How to Identify Ancient Roman Coins
A practical workflow for identifying Roman coins from portraits, legends, reverses, mints and standard references.
Updated 2026-07-19
Begin with the physical evidence
Record the metal, diameter, weight and die axis before trying to name the ruler. These measurements separate denominations that can share very similar designs. Photograph both sides in even light and preserve the orientation of every inscription.
Do not clean a coin to reveal more detail. Surface deposits and patina can contain evidence of age and manufacture, while aggressive cleaning permanently removes metal and collector value.
Read the portrait and obverse legend
Roman imperial coins usually place the issuing authority on the obverse. Work outward from distinctive letter groups rather than guessing an entire worn legend. Titles such as AVG, CAES, IMP, COS and TR P help date an issue but are not unique names.
Compare the portrait, bust type, headgear and direction with securely attributed examples. A radiate crown can indicate a dupondius or antoninianus, while a laureate head occurs across many denominations.
Decode the reverse and mint marks
Identify the reverse figure, attributes and short legend independently. A standing deity, military standard, captive or architectural type often narrows the reference quickly. Exergual letters below the design commonly identify the mint and officina on later Roman coins.
Use the BidArch mint archive to compare ancient place names, regions and recorded types. Mint marks changed over time, so a mark should always be tested against the ruler and denomination.
Confirm with references and provenance
Confirm an attribution with a standard catalogue such as RIC and at least one photographed specimen. Match the complete combination: ruler, denomination, obverse legend, bust, reverse legend, reverse type, mint and field marks.
Record collection labels and prior auction appearances. Provenance is part of the object history and can be as important as the attribution itself. BidArch archive and auction pages preserve searchable reference and sale context.