The Decline of the Antoninianus



The antoninianus denomination tells a tale of the Roman Empire during a period of crisis and unceasing transformation, and is an important part of Roman monetary history. The antoninianus was introduced by Emperor Caracalla (nicknamed after Gallic hooded tunic he wore) in 215 AD, due to his problematic financial situation. The name “antoninianus” comes from Caracalla’s real name Marcus Aurelius Antoninus. Initially, the coin was in silver but later on heavily debased by mixing in bronze. The antoninianus was first valued at 2 denarius, although it’s initial silver content only was worth 1.5 denarius. Seigniorage is the difference between the value of money and the cost to produce it (price spread), essentially it’s the profit that a government earns by producing currency and can be seen as a form of inflation tax. The word comes from old French seigneuriage, “right of the lord (seigneur) to mint money”. The seigniorage of the antoninianus created inflation as shopkeepers had to raise their prices to match the debased new currency. Allegedly, people started to collect the denarius (the older silver denomination) and pay with the antoninianus. This is consistent with Gresham’s law that states that “bad money drives out good money”. If two types of commodity money circulate and are legally recognized as having equivalent face value (nominal value), the commodity with the higher intrinsic value (the value of the precious metal, e.g., silver) will gradually be withdrawn from circulation. At this point in time, the Roman Empire did not expand and its current silver mines where running short, therefore the antoninianus was minted with less and less silver over time, leading to an increasing inflation. In the late third century the antoninianus was almost fully debased to bronze. This lead to a hyperinflation not unlike the Weimar Republic in 1920s Germany.

Silver content of the antoninianus

Even in the beginning antoninianus coins were not made of pure silver. Initially, the antoninianus was minted with up to 80% silver. However, during Caracallas reigns the antoninianus was depleted to a silver content of around 50%. In the late 3rd century the silver content of the coins were merely 5%. The antoninianus stopped being produced around the time of Emperor Diocletian’s currency reforms which began in 294 AD. Diocletian introduced a variety of new coins, most notably the “nummus,” also known as the follis. These reforms were part of his broader efforts to stabilize the Roman Empire, which at the time was suffering from inflation, civil wars, and external threats.

During the time the antoninianus coins were produced it was common with a “depletion silvering” technique. In this process, coins were made from a base metal core (usually bronze or copper) and were then treated to give them a surface layer of silver. Here’s a simplified explanation of how depletion silvering could work:

This method was less expensive than using pure silver but gave the coins a similarly valuable appearance, at least when new. Over time, however, the surface silver layer could wear away, revealing the less valuable base metal underneath. The depletion silvering technique is an interesting example of ancient metallurgy, revealing the kinds of compromises and innovations that civilizations have made in the face of economic challenges.

A set of antoninianus over time

Below is a picture from my collection showing the decline of the antoninianus over time,

Attribution of the coins in the picture

Coins in the Roman Empire were a source for propaganda and they tell interesting stories. Today these stories both consist of the mythical Roman stories, but also the tide of history they tell.

1st coin: Antoninianus Caracalla (198-217 AD)



This coin is very interesting as it is an antoninianus from the first year the denomination was minted. Caracalla introduced the denomination in 215 AD and this is one of the examplars from that year.

2nd coin: Antoninianus Philip the Arba (244-249 AD)

Resources for the coin:


I recently acquired my first ancient roman coin, which is an Antoninianus from around 244-247 AD. The obverse of the coin depicts a bust of Philip the Arab with a radiate crown, a type of crown that has spikes or rays emanating from it, often used to symbolize divinity or a connection to the sun god, Sol. On the coin, the radiate crown indicates that the denomination is the antoninianus, also called the pre-reform radiate.

The observe legend “IMP M IVL PHILIPPVS AVG” translates to “Emperor Marcus Julius Philippus Augustus”. Where “IMP” stands for “Imperator”, and the rest is his name, “M” for “Marcvs”, “IVL” for Ivlivs (Julius), and “AVG” for “Avgvstvs”. Augustus was a Roman title that means “venerable” or “consecrated”. It was adopted by the first Roman Emperor, Gaius Julius Caesar Octavianus (often referred to simply as Augustus), who reigned 27 BC - 14 AD. Thereafter, Roman emperors added the title to their regnal names.

The reverse legend “ROMAE AETERNAE” translates to “Eternal Rome” in English. This phrase often appears on Roman coins and other inscriptions to pay tribute to the everlasting nature of the city and the empire. It reflects the Roman belief in the perpetual endurance and grandeur of Rome, a sentiment that was widely propagated during various periods of the Roman Empire.

On the reverse of the coin you can see Roma seated with a shield. She is holding Victory in her right hand and a long scepter with her left. In ancient Roman religion, Roma was the personification of the city of Rome and the Roman state. In Roman artwork and on coins, she is often portrayed in a military guise, with a helmet and carrying weapons. Her portrayal, seated with a shield and spear, later inspired the image of Britannia, the personification of Britain. The small figure of Victory, often depicted with wings, symbolizes a military triumph. The scepter is a traditional symbol of authority and governance, emphasizing the lawful and just rule of the emperor and the state.

Identifying the coin can the done on the American Numismatic Society’s website. I searched for the observe and reverse legends (IMPPHILIPPVSAVG and ROMAEAETERNAE) and that yielded 7 possible results.

Ancient coins can have many variations, even within the same emperor’s reign or from the same mint. Minor differences in design, inscriptions, or wear can create challenges in identification, so having access to specialized resources or professional guidance may prove invaluable in determining exactly which coin you have. Roman coins were struck by hand, and I have heard that the reverse die could wear out quicker than the observe die, meaning that the same observe die could be used with several different reverse dies.

3rd coin: Antoninianus Postumus (259-268 AD)


Attribution: Resources:

4th coin: Antoninianus Carinus (282-283 AD)


The portrait on the observe on this coin is Carinus who was the son and co-emperor of Carus. Carus was emperor 282-283 AD and when he died he was succeeded by his sons Carinus and Numerian.