Published at 30th Oct 2023
Modified at 30th Oct 2023
Collecting Ancient Roman Coins Part IV: Identifying the Denomination
Collecting Ancient Roman Coins Part IV: Identifying the Denomination
From Augustus to Diocletian 27 BCE - 286 CE.
When you’ve identified the issuer and dated a Roman Coin, the denomination is the last step. Modern coins often have their denomination marked on the Obverse or Reverse, Roman coins weren’t so simple as there was lots of other information on the coin taking up space. In Roman times the metal, weight and diameter of the coin were the most important factors for value.
The most important denominations for the period 27 BCE - 286 CE are listed below.
GOLD COINS
Aureus - A gold coin of the highest denomination. Its very name hints at what it is made from as the Latin for gold is Aurum. The Aureus was first minted around 210 BCE but it was an unusual coin, with a high value. The Republican pieces are rare.
From Augustus, it was a gold coin of high purity, around 23 k, and a weight of 7.9 - 8 grams. The diameter was around 19-21 mm. Its value was equal to 25 Silver Denarius. As with most coins of the Roman Period it had the Emperors bust on one side, or a family member and on the other various scenes.
During the reign of Nero (64 CE), the weight of the coin was reduced to around 7.6 - 7.7 grams. From the second century CE the purity was reduced to around 22 k gold. From the time of Septimius Severus and his son Caracalla the weight was reduced again to around 6.5 - 7 grams. In the third century CE the weight varied from emperor to emperor, often influenced by political and military situations as a result of pressure put on the financial system. During this period the weight varied from around 3.5 grams to 5.5 grams. Some Aureus minted during the rule of Diocletian weighed around 5.4 grams.
The Aureus is a very rare coin, and one that is on most Roman Coin collectors’ wish list. Current values for this coin vary, but $3,000-$4,000 is not uncommon, with better examples going for much more. Rare examples such as from an emperor that didn’t issue many or a more unusual reverse easily break the $10,000 barrier, even in average condition. Gold coins are soft and are not often found in exceptional condition. VF (Very Fine is much easier to find than EF or the elusive UNC.
Quinarius Aureus - The golden half. This coin represented 1⁄2 of an Aureus, and was also half of its weight. It is a rare coin that was seldom seen in circulation. The minting of this coin wasn’t common either. It weighs around 4 grams and has a similar appearance to an Aureus. From the third century, it disappeared from circulation as the Aureus was getting lighter and lighter in weight, making this an impractical and uneconomical count to produce.
The diameter was a fairly constant 15 - 16mm.
Due to their rarity when made, they are even more rare now. Often examples of these can sell for more than an Aureus.
SILVER COINS
Denarius, this was the standard coin in the roman system and probably the most well known. It’s made from silver which is why it’s sometimes referred to as a “Denarius Argenteus”, with Argenteus meaning silver. Its denomination was worth approximately 1/25th of a Gold Aureus, or 16 Asses (see below).
It was first minted around 210 BCE, in the time of the Roman Republic. When it was first made, its value was 10 Bronze asses (rather than 16 near its end). The name “Denarius” comes from the word “Decem” meaning 10, as December was when there were only 10 months in the calendar. Its weight was around 4.4 grams when first introduced. During the reign of Augustus, the weight was reduced to around 3.9 grams. From 64 AD, Nero reduced the weight again to around 3.5 grams. From the second century CE, the weight of the Denarius dropped yet again to around 2.5 - 3.3 grams, but heavier examples of around 3.8 grams aren’t unusual.
The diameter was 17-18 mm for the Denarius in the first century. At the beginning of the second century, the coin got lighter and thinner resulting in a slightly larger diameter of 18-20 mm. Starting with the first part of the reign of Septimius Severus, the Denarius was minted as a thicker coin with a diameter of 15-17 mm. During the second part of his reign, after 202, it became a thinner, larger coin of around 18-21 mm.
The purity of silver was approximately 90-93 %, in the beginning. From the reign of Trajan, 98-117, it was reduced to 70-80 %. Septimius Severus minted denarius at around 50-70 %. The remaining percentage of metal was often copper. Sometimes, these coins were made from bronze and only silver plated.
In the third century, inflation meant that its value dropped and it soon became a coin that wasn’t economical to mint. After 238CE, it was rarely seen in circulation.
The Denarius is one of the most common, and recognisable, coins of the Roman Empire. It was minted in large quantities so there are a fair few on the collectors market. They are a great addition to any collection.
Usually the Consecratio theme or the family coins, with more than one family member are rare.
As this denomination was in circulation for so long, it’s difficult to find great examples. Some are hard to find in VF (Very Fine) condition and some examples are almost impossible to find in EF/XF (Extremely/Extra Fine) condition.
Quinarius Argenteus represents half a Denarius. It’s a silver coin that is half the weight of a Denarius, usually around 1.2 - 1.7 grams. In appearance, they are similar to the Denarius but the size and weight give them away. It’s a very rare coin, hard to find and usually very expensive.
Antoninianus has a value of 2 Denarius. It was introduced in 215 and as a distinctive feature, the emperor’s head has a radiate crown, while the Empress has a lunar crescent over her shoulders. It had a diameter of 23-25 mm and initially a weight of 5.5 grams. The silver content was only 50%.
After 238, it lost weight, to around 4.5 grams. After 251 it became a Bronze coin, with only 3-5 % silver which was applied as a coating or plating.
It was also much lighter, around 3 grams. Even so, light pieces can be found. Aurelianus, 270-275, tried to improve this coin by increasing its size and weight, as well as the silver content, but it didn’t . It disappeared from circulation after Diocletian reform.
BRONZE COINS
A Sestertius is a quarter of a Denarius. It was originally made from silver but from Augustus, this was minted in bronze. It usually bears the mark HS to indicate its value.
It has a diameter of 25 - 40 mm, and a weight of 25 - 27 grams. The size of the coin means that it was possible to portray some superb scenes in a good amount of detail. In the third century, it started to lose value and weight, after the second half of the century it disappeared from circulation.
This coin is usually hard to find. Fine examples can command a high price, especially for rarer issues and more interesting reverses.
Some of the most spectacular pieces are the ones with buildings. For example there is an example of Nero’s depicting the Port of Ostia (dedicated to his wife).
Dupondius was a coin made from orichalcum, a bronze alloy which can vary greatly in its composition. It weighs around 13 grams and the diameter can vary in size. It was equal to half a Sestertius, or two as. After 64 CE, its distinctive mark was the radiate crown that seated on the emperor’s head.
These coins are scarce, but decent pieces can be found.
The As is the basis of the Roman currency. It was a coin made from bronze. During the Republican time, it had different weights, from 1,5 kg (aes rude), being cast as “nuggets” and ingots, more of a proto money than what we would recognise today. It soon lost its weight and became more recognisable as a coin (aes grave), but with a weight of between 272 and 341 grams, it was far from pocket change. In 89 BCE, the weight was considered equal to one avoir de pois ounce (28 grams), (aes uncial). Augustus minted asses at around 10 -11 grams made of bronze. The first century CE pieces are plain and simple but usually rare. The second and third century CE pieces are more common.
The cost of these coins can vary greatly and it is difficult to obtain a high condition piece.
Semis was a denomination minted since Republican times, but it is a rare coin as there were few periods where it was minted. Its value was equal to half of an as, as the name suggests (semis=half).
Quadrans were a quarter of an as, as the name states (quadrans=quarter). Also a rare coin. Again, this was a coin minted since Republican times. In Imperial times it was very rarely minted.
It was the least valuable coin in circulation. Cicero used the word quadrantaria to describe something very inexpensive.
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