How to Identify the Constantine the Great Follis

What This Coin Is

This bronze follis, also called a nummus in later, reduced-size forms, was struck under Constantine the Great, who reigned from AD 306 to 337, spanning the late Tetrarchic system through his sole rule and the founding of Constantinople.

Obverse Design

The obverse shows a laureate, helmeted, or diademed bust of Constantine facing right, typically in cuirass or paludamentum. The legend usually reads IMP CONSTANTINVS AVG or a similar variant tracking his changing titles from Caesar to Augustus.

Reverse Design

Early folles often carry the legend SOLI INVICTO COMITI, depicting the sun god Sol standing radiate and holding a globe. Later in the reign, the common GLORIA EXERCITVS type shows two soldiers flanking one or two military standards. Other types include vota wreaths marking anniversary vows and commemorative city issues such as Urbs Roma with the wolf and twins, or Constantinopolis with Victory on a ship's prow.

Size, Weight, Metal, and Edge

The follis shrank considerably over Constantine's long reign, from a larger module early on, around 20-24mm, down to smaller pieces later, often under 18mm. It was struck in a bronze or copper alloy, with a thin silver wash on some earlier issues that mostly wore off in circulation, and has a plain edge.

Mint Marks and Where to Look

The exergue at the bottom of the reverse carries a mint mark abbreviation, such as PLG for Lugdunum, SMANT or SMANTA for Antioch, and TRP or PTR for Trier, along with similar codes for Rome, Ticinum, Siscia, Thessalonica, and other imperial mints, often followed by an officina (workshop) letter or numeral.

Telling It Apart From Similar Coins

Compare against the earlier, larger folles of the Tetrarchy under Diocletian and Maximian, which are heavier with a GENIO POPVLI ROMANI reverse, and against Constantine's sons' later coinage, which continues the shrinking module and introduces new reverse types after his death. The specific combination of bust style and reverse legend narrows the issue.

Grading at a Glance

Assess centering and legend completeness first, since later, smaller folles were often struck off-center on tight flans. Check the soldiers' or Sol's facial and drapery detail for strike sharpness, and note that a mostly worn-off silver wash is normal on earlier examples rather than a defect.

Authenticity Red Flags

Verify the mintmark makes sense for the claimed type and period, since mismatched or garbled mintmark letters can indicate a modern fake. Watch for overly smooth, low-relief surfaces suggesting a cast copy rather than a struck coin, and compare weight and diameter to genuine examples from the same approximate date in the reign.