NGC Ancients: Roman Bronzes Appeal to Specialist Collectors

Posted on 4/11/2017

The early Romans’ appreciation for copper money remained strong through the collapse of the Roman Empire.

In the ancient Greek world there was a strong preference for precious metal coinage. Base metal coins were added to the mix only long after gold, silver and electrum coins had come into regular use – and even then, fractional silver coins continued to compete with the ‘token’ base metal coins.

A cast copper as of the Roman Republic (issued c.225 to 217 B.C.)
Click images to enlarge.

The same cannot be said in the Roman world – at least in the formative years of the Republic. The early Romans had a clear preference for copper: they issued countless tons of copper coins (and pre-coinage copper lumps and bars) and rarely struck silver coins – and never gold – before Hannibal’s catastrophic invasion of Italy in the winter of 218 B.C.

The resulting Second Punic War (218 to 201 B.C.) forced the Romans to rethink their monetary policy, which ultimately came to favor silver and gold. Even so, a fondness for copper (and its principal alloys: brass, bronze and leaded-bronze) remained strong enough to assure that base metal coins would be struck until the collapse of the Roman Empire late in the 5th Century A.D.

Rome’s first emperor, Augustus (27 B.C. to A.D. 14), organized the Roman monetary system to include a variety of base metal coins. In the early empire there were five core denominations, examples of which – all from the reign of Hadrian (A.D. 117 to 138) – are illustrated below.

A copper as of Hadrian.
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The main denomination was the copper as, which typically weighed between about 8 and 12 grams and was about 23mm to 30mm in diameter.

A brass dupondius of Hadrian.
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Worth two asses was the dupondius, which typically was made of brass (though later examples usually are of a lesser alloy, or copper). It was about 25mm to 30mm in diameter, and typically weighed somewhere between about 11 and 16 grams. The portraits of male rulers on these coins most often are adorned with a radiate crown, and those of females rest upon a crescent.

A brass sestertius of Hadrian.
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A large and heavy base metal coin – the sestertius – was valued at four asses. Like the dupondius, it typically was made of brass in the early years of the empire, but later came to be struck in a lesser alloy. Early examples are about 30mm to 35mm in diameter and usually weigh somewhere between 18 and 30 grams.

Though the most commonly struck base metal coins were the as, dupondius and sestertius, the Romans also struck fractions of the as, including the semis and the quadrans.

A brass semis of Hadrian.
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The semis appears to have been valued at half an as. It was struck in both brass and copper, typically was about 17mm to 20mm in diameter, and most often weighed somewhere between 3 and 4.5 grams.

A copper quadrans of Hadrian.
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The smallest of the regular-issue imperial bronzes was the quadrans, which likely was valued at a quarter of an as. This small coin was struck in copper (though they rarely were struck in brass), typically weighed between 2 and 3.5 grams, and was about 13mm to 18mm in diameter.

Unlike Roman precious metal coins, which often survive with pristine surfaces, bronzes were significantly more vulnerable to oxidization and the corrosive effects of soil. For this reason, collectors of early Roman Imperial bronzes must be accepting of less-than-perfect surfaces – especially if they hope to acquire more than just a handful of coins.

Shown below are six coins that illustrate surface conditions commonly encountered on ancient Roman bronze coins.

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Occasionally a base metal coin will survive with surfaces that are described as having a “river patina” or a “Tiber patina.” Such coins are truly rare, and should not be confused with bronzes that have been cleaned and then toned to mimic this lofty surface condition. Above is a brass sestertius of Nero (A.D. 54 to 68) with nearly perfect surfaces.

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After many centuries of burial, ancient bronzes usually develop surface encrustations typically are called patinas. These patinas range from extremely unattractive to positively delightful, and they greatly affect collector value. Above is a brass sestertius of Trajan (A.D. 98 to 117) with a desirable green patina.

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The brass sestertius of Galba (A.D. 68 to 69) shown above possesses two very different surfaces: its obverse has an attractive surface and its reverse has suffered extensive corrosion.

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Areas of red and green encrustation adhere to a sestertius (above) of Manlia Scantilla, who briefly reigned as empress in A.D. 193. The deposits are securely attached to the surface and any attempt to remove them would leave significant traces of that effort.

Click images to enlarge.

The surface of this brass sestertius of Nero (above) originally was covered with encrustation. Someone with less-than-ideal conservation skills removed most of those deposits with a metal tool. The cleaner did not attempt to remove encrustation from the peripheries, but focused on the areas from the inscription inward. The portion which received the cleaner’s attention suffered what is traditionally described as “smoothing.”

Click images to enlarge.

The copper as above, struck in posthumous honor of Augustus’ talented general Marcus Agrippa (died 12 B.C.), is corroded and appears to have been smoothed. It also has an isolated spot of bright green verdigris (most often called ‘bronze disease’), which is a live and active condition that unless arrested will eventually destroy the coin.

Interested in reading more articles on Ancient coins? Click here

Images courtesy of Classical Numismatic Group.

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