Roman coinage of the first 2 centuries of the Roman empire is well documented and allows for relative clarity in its study and collection. However by the 3rd century reforms were increasingly required but less well documented, the “Antoninianus” was introduced but the name itself is a modern invention in line with the emperor who introduced it (Caracalla). The Roman monetary system becomes extremely opaque to us with Diocletian’s monetary reforms of 294AD.
During the late Roman Empire of the third century AD, there were different coin denominations in circulation, with fluctuating value and physical characteristics. A breakdown of the different coin denominations is provided below, also including some indications of their relative value, size, and other qualities. The list includes 5 basic denominations, the last of which “AE” can be broken down into a further four “AE1-4”. It is worth noting that both “Antoninianus” and “AE” are modern fabrications.
We then go on to provide a sense of the coinage from the 4th century, with its different denominations and unclear corresponding values from highest value to lowest:
1 – Gold Aureus
This was the highest-value coin in the Roman Empire, made of gold and typically weighing around 6 grams. During the third century AD, an aureus was worth 25 Denari or 250 Aes. In later times it was to become a “Gold Solidus“…
2- Antoninianus or Aurelianus
This silver coin was introduced in 215AD by Caracalla and became the standard silver denomination throughout the Empire for almost a century until Diocletian’s coinage reform of 295AD. The Antoninianus replaced the earlier silver Denarius as a ‘double denarius’.
The name is a modern attribution based on the emperor who initiated it because the actual name of this coinage is not known.
It typically weighed around 4-5 grams and measured around 22-23 mm in diameter. It was typically worth around 20-30 AE.
The silver denarius had been the primary silver denomination during the earlier Roman Empire and Republican period. In many ways it was the backbone of Roman coinage and used to pay the military troops. It was effectively replaced by the Antoninianus which was introduced as a “double denarius” (though it didn’t actually have twice the silver content!).
The typical weight of a Denarius was supposed to be around 4-5grams of pure silver though it was gradually debased. During the third century AD, its value had declined due to inflationary pressures and continuous debasement as low as 2-3 AE.
3 – Follis
Until relatively recently the Follis of this period was thought to be a bronze coin introduced in the early 3rd century AD as a replacement for the Sestertius, or possibly used as a substitute name for a coin denomination introduced in 294AD. It was the largest and heaviest of the base-metal denominations, typically weighing around 10-15 grams and measuring around 25-30 mm in diameter.
It is now becoming evident that the term Follis was misunderstood, possibly relating more to the practice of applying a thin silver plating to the largely bronze coinage; and the term Nummus is possibly more appropriate. This creates a further overlap with the modern usage of the AE denomination (see below) to denote smaller bronze/copper coinage. ie Follis = Nummus = AE ?
The primary large denomination in the Roman Republic and Empire was the bronze sestertius. However, during the third century AD, its value had declined significantly, and it was worth around 1/4 AE. Sestertii typically weighed around 20-28 grams and measured around 30-35 mm in diameter. Perhaps replaced by the Follis or simply given a fresh shine of silvered surface.
4 – The Dupondius faded away
The dupondius was a denomination which had started as early as the Roman Republic and became extinct around the later 3rd century AD. It was typically distinguished from the lower value copper Aes coins of the Republic by the use of a radiate crown. The radiate crown went on to be used for the Antoninianus to show its greater value than the denarius. It typically weighed around 10-15 grams and measured around 25-30 mm in diameter.
During the 3rd century the dupondius was a smaller brass coin worth half the value of a sestertius/follis, or around 1/8 AE.
5 – AE (AE1-AE4)
The AE is a modern attribution to call small bronze coins of low value, largely based on their size. The exact value of an AE coin could vary widely and the denominations remain unclear. We tend to break them down by size into AE1, AE2, AE3, and AE4, which weigh around 10-15 grams, 4-6 grams, 2-3 grams, and less than 2 grams, respectively.
AE1: typically measured >25mm, ie around 27-34mm in diameter.
AE2: around 22-27mm in diameter.
AE3: 17-21mm in diameter.
AE4: were the smallest denomination coins <17mm in diameter.
Roman coinage from the 4th to the 7th century
The denominations and value of ancient Roman coinage further developed during the later Roman empire from the 4th century, particularly under events such as the fall of Rome in the west and a consolidation of power into the Eastern half of the Empire at Constantinople. The confusing overlap between Follis, Nummis and AE has already been touched upon and not helped by the fact that Emperor Constantine introduced a series of bronze coinage denominations which further muddy the waters. He also upgraded the higher end of the scale, eliminating the Aureus and introducing the gold Solidus.
The Byzantine (Roman) Empire further reformed coinage and reintroduced the use of Follis and Nummis. around the year 500AD with the reform of Anastasius. A Follis was equivalent to some 40 Nummi…
Conclusion about Roman coinage denominations of the late empire:
It is important to note that the values, sizes, and other characteristics of these coins depended on factors such as the emperor, the mint, economy and period. ie they were highly variable. The relative value of each denomination could fluctuate over time depending on factors such as inflation, economic conditions, and political stability.
Frequent denominations and commonly used labels are summarised in the table below though their precise relationship and value is not always clear nowadays.
Republican and early Imperial coinage system:
Late Imperial Roman coinage system:
– Aureus – 25 Denari – Denarius (made of Silver) – 10 As – Sestertius – 2.5 As (later changed to 4As) – Dupondius – 2 As – As – 12 ounces – Semis – 6 ounces – Triens – 4 ounces – Quadrans – 3 ounces – Sextans – 2 ounces – Uncia (1 ounce, base unit)