Denomination of old roman coins.

[papa_joe]

Recently i have started to collect roman coins. I have made some research about the reverse figures and the obverse, the emperors figures etc. But there is one major thing i cant understand and that's the denominations of the coins. i know there are   denarius ,  sestertius, as etc, but how do i know what is the denomination of a certain coin?

[Finn235]

Roman coin denominations are actually simple enough to understand, at least until the last 200 years of the empire.

To start, there were four principal metals:

Gold, or AVRVM (AV)

Silver, or ARGENTVM (AR)

Orichalcum, a high-zinc brass said to look just like gold, and worth twice as much as bronze (Usually grouped with bronze as AE)

Bronze, or AES (AE)

On to the denominations:

Aureus - A very valuable coin worth 20 silver denarii, weighing about 8 grams and the size of a US dime (17-19mm usually).

Denarius - A roughly dime-sized silver coin with 4 sesterces or 16 asses. Forv the common man, this was "big money" worth several days' salary as a soldier.

Sestertius - A huge orichalchum coin worth four asses; usually a bit smaller than a silver dollar, but very thick and hefty. This was everyday money with good spending power. The emperor's portrait is usually bare or laureate.

Dupondius - A roughly half-dollar size orichalchum coin worth two asses. Starting with Nero, the emperor's portrait wears a radiate crown, indicating a double denomonation.

As - A roughly half-dollar sized bronze coin worth enough for about a large loaf of bread. The emperor's portrait is laureate or bare.

Semis - A roughly nickel or penny sized orichalchum coin worth 1/2 of an as, not commonly issued. They don't always feature the emperor's portrait, and are really only common from Trajan.

Quadrans - A roughly dime sized orichalchum or bronze coin worth 1/4 of an as. This was "beggar's money" with negligible buying power and only Intermittently issued.

***

In 215 AD the emperor Caracalla began issuing an "Antoninianus" or double-denarius; a roughly quarter-sized silver coin featuring a radiate crown for the emperor. These were intermittent issues (being briefly outlawed due to their detrimental effect on the economy; they did not contain enough silver) but inflation made them replace the denarius around 240, and by the 250s they had inflated to the point of driving out all other denominations. By the 260s they were less than 5% silver; essentially bronze with a thin silver plating. It's not fully understood how much buying power they had, but it wasn't much.

[Finn235]

In the late 280s or early 290s, emperor Diocletian attempted to fix the financial situation by demonetizing all old coinage and starting over from scratch. He was somewhat successful, but was never able to successfully reintroduce silver as it had been used a century prior. His denominations:

Aureus - Carried over, as it had never been fully debased. Worth 24 Argentii.

Argenteus - Spiritual successor of the denarius, but not commonly issued and probably worth much more. Worth 5 folles.

"Follis" - Large heavy silver plated bronze coin; not quite as large or heavy as the old sestertius

"Radiate" - bronze, unplated coin featuring a radiate portrait; roughly the size of an old antoninianus. Value not fully understood.

"Laureate" - Bronze coin featuring a laureate portrait for the emperor, perhaps exchangeable 1:1 for the antoninianus as it seems to be the smallest denomination.

 

Diocletian's Tetrarchy system erupted into civil war not long after he abdicated in 305. When the dust settled, only Constantine and Licinius were left, and the currency had inflated tremendously; the follis shrinking down to about the size of a nickel. From this point, we simply don't understand how the bronze coinage worked, so the following groupings are used:

AE1 - Rare, large bronze coin about the size of Diocletian's follis. 25mm or larger

AE2 - Between 25-21mm, or roughly quarter/nickel sized.

AE3 - 21-17mm or peny/dime sized

AE4 - below 17mm - these can be as small as 9mm!

AE2 and AE3 coins were commonly plated in silver until about 260.

As with the Tetrarchy, precious metal coins are not common.

Solidus - a "light" successor to the aureus, weighing about 4.5 grams

Semissis - 1/2 solidus (introduced near the end of the empire)

Tremissis - 1/3 solidus (a relatively common tiny gold coin of the terminal empire)

Siliqua - A thin, lightweight silver coin about the size of a denarius. These were either seldom used in their day, or most were melted in the middle ages. Fractional denominations also issued.

By the 400s, most coins were tiny little AE4s, or siliquae or solidii. Roman coinage is said to end when Byzantine emperor Anastasius issued a reform to re-introduce large denominations in 491.

[papa_joe]

Thank you so very much. 

[thedeadpoint]

I've been on this site for 12 years and that's the first time I've seen Roman denominations explained. Thank you!