Last reviewed: 13 October 2026 · Aurora Antiqua Editorial
Quick answer: Roman coin letters often abbreviate a ruler's name and titles. IMP stands for Imperator, AVG for Augustus, COS for Consul, and TR P refers to tribunician power. Read the letters with the portrait, reverse design and catalogue type, rather than treating a single abbreviation as a date or proof of authenticity.
Browse our Roman coins to compare the individual photographs, descriptions and proposed catalogue references.
Start with what is actually visible
A coin legend is its inscription. Record the front, or obverse, separately from the back, or reverse. Begin with clear groups of letters, then note any damaged or missing parts. Expansion and translation are later steps: the letters you can see, the words you think they abbreviate and their English meaning should remain distinguishable.
The Ashmolean Latin Inscriptions Project's teaching pack explains how editorial notation distinguishes surviving text from supplied readings. Its examples concern inscriptions more broadly; they provide a reading method, not a coin authentication test.
Common abbreviations on Imperial coins
The following are useful starting points for Latin Imperial legends. Spacing and abbreviated forms vary, and the full inscription supplies the context.
| Letters | Reading | What to check |
|---|---|---|
| IMP | Imperator, an imperial title | Its position in the full titulature. |
| CAES | Caesar, a name or title | The named person and coin type. |
| AVG | Augustus, in this Imperial context | The complete wording and any variant ending. |
| P M / PONT MAX | Pontifex Maximus, chief priest | The surrounding titles. |
| TR P / TRIB POT | Tribunician power | Any following numeral and the ruler's chronology. |
| COS | Consul | A following numeral records the consulship count. |
| P P | Pater Patriae, father of the fatherland | Its place in the legend, rather than reading separate words from each P. |
| S P Q R | Senatus Populusque Romanus, the Senate and People of Rome | Read the rest of the reverse formula too. |
Do not expand a short fragment just because it resembles one of these entries. Identify the likely ruler and type, then test that interpretation against the surviving letters on both sides. Modern transcriptions can also separate words that run together on the coin.
A documented worked example: Trajan
OCRE, RIC II Trajan 182, records a silver denarius from Rome, dated 103 to 111 CE. This is a catalogue type used to demonstrate the reading; it is not an attribution of an Aurora product.
Obverse: IMP TRAIANO AVG GER DAC P M TR P COS V P P
Reverse: S P Q R OPTIMO PRINCIPI
TRAIANO identifies Trajan. IMP and AVG give titles; GER and DAC abbreviate Germanicus and Dacicus. P M and TR P add priestly and tribunician titles. COS V records the fifth consulship, and P P adds Pater Patriae. The reverse names the Senate and People of Rome and addresses the ruler as the best princeps.
The catalogue also describes the reverse figure and its attributes. Those details matter: another type may share some of these letters. Use the recorded 103 to 111 CE range for this example rather than claiming the words alone establish a particular year.
Use the design and mint marks as well
The American Numismatic Society's guide to the OCRE identification tool shows how partial legends, portraits and metal can help narrow a search. Compare the reverse figure and visible objects as well as the lettering. A similar name is a candidate for comparison, not a completed identification.
Letters, numbers and symbols below or beside a reverse design may help distinguish an issue. They are not a universal mint-name dictionary. Before assigning a mint or workshop, compare the mark in its position with the recorded type and examples.
When a letter does not match
The British Museum records a Constantine coin, 1982,1034.29, with AG in place of AVG in the obverse inscription. That particular recorded variant demonstrates why a mismatch deserves investigation. It does not establish a general rule that an unusual legend is genuine, or that correct spelling proves authenticity.
If an inscription is worn, ask for a clearer photograph before accepting an expansion. Check the proposed ruler, denomination, weight, design and catalogue reference together. Read our Roman coin authentication guide for Aurora's approach, and the provenance and authenticity page for our documentation and guarantee.
Frequently asked questions
Does COS V give the exact year of a coin?
It records a fifth consulship in this context. Match the full legend, ruler and reverse type to a catalogue; the numeral alone is not an exact issue date. The Trajan type used here is catalogued within 103 to 111 CE.
What does TR P mean on a Roman coin?
TR P refers to tribunician power. A following number can help with dating when checked against the ruler's sequence of titles and the identified coin type. Do not read it as a calendar year on its own.
How should I record letters that I cannot read?
Keep the surviving letters separate from any proposed reconstruction. Mark gaps and uncertainty in your notes, compare both sides with catalogue examples, and do not silently turn a guess into a visible inscription.
Does an unusual letter prove that a coin is fake?
No. A British Museum coin of Constantine, registration 1982,1034.29, is recorded with AG rather than AVG in its obverse inscription. This specific variant is a reason to check a type and its recorded examples, not a rule that authenticates an unfamiliar coin.
Do all Roman coins follow this Latin Imperial pattern?
No. This guide focuses on Latin legends on Roman Imperial coins. Republican and provincial issues need their own catalogue context; a fragmentary legend should not be forced into the Imperial example shown here.
Sources and further reading
- Ashmolean Latin Inscriptions Project, Secondary Resource Pack: editorial notation and abbreviated titles.
- OCRE, RIC II Trajan 182: the worked coin type and catalogue date.
- American Numismatic Society, Identifying Roman Coins: practical use of OCRE.
- British Museum, Constantine coin 1982,1034.29: a specific inscription variant.
- American Numismatic Society online resources: OCRE and the separate Republican catalogue, CRRO.
For a first purchase, continue with our Roman coin buyer's guide, or return to the Roman coin collection. The individual listing's surviving letters and recorded evidence should guide your choice.