NGC Ancients: The Decline of Roman Imperial Silver Coinage, Part I

This denarius of Claudius is also about 98% pure silver.

For the first 90 years of the Roman Empire, when members of the Julio-Claudian family reigned, the purity of Rome’s silver coinage was unassailable: a solid 98% pure or higher. That standard was maintained by the emperors Augustus, Tiberius (14-37), Caligula (37-41) and Claudius (41-54), and even Nero (54-68), who didn’t change it for the first decade of his reign.

However, the Great Fire of Rome in 64 marked the start of a debasement that would take about two centuries to unfold, eventually bringing Rome’s silver coinage to an unfathomable low.

The cost of rebuilding the razed areas of the capital was extraordinary. Nero chose the quickest and most efficient pathway to raising funds – re-coining old money into new money of lesser intrinsic value, with Nero’s treasury pocketing the difference.

A pre-reform denarius of Nero, about 98% pure silver.

A post-reform denarius of Nero, about 93% pure silver.

At the Rome mint, he decreased the purity of silver denarii by 5%, dropping it from about 98% to about 93%. Simultaneously, he reduced the weight of the denarius by about 12.5%, which further reduced the actual silver weight of the coin.

Nero also reduced the weight of his gold aurei, and was even more aggressive in his intrinsic reductions of two major provincial coinages, the silver tetradrachms of Antioch and the billon tetradrachms of Alexandria.

A Vespasian denarius, perhaps 89% pure silver.

Nero was overthrown in 68, giving rise to a terrifying civil war that raged into 69, the infamous Year of Four Emperors. In the aftermath of the war a new emperor, Vespasian (69-79), came to power. Not surprisingly, there was a catastrophic need for funds, so he reduced the purity of the denarius further still, from Nero’s post-reform 93% to about 89%.

The denarius remained at about 89% pure (though sometimes it dipped to as low as 80%) until the year 82, when Vespasian’s second son, Domitian (81-96), was emperor. He took the bold measure of restoring the purity of the denarius to the lofty Augustan standard of about 98%.

A denarius of Domitian issued in 84, during the brief high-purity period.

This was a fortunate circumstance, but did not last long: just three years later, in 85, Domitian dropped the purity of the denarius down to Nero’s post-reform standard of about 93%, where it more or less remained for more than 20 years.

Then, in 107, the emperor Trajan (98-117) reduced the purity of the denarius by a further three or four percent, bringing it down to c.89% to 90% silver. From there the purity slid gently until 148, when the emperor Antoninus Pius (138-161) removed about another 5%, bringing the denarius to about 84% or 83% pure.

This Antoninus Pius denarius is perhaps 84% or 83% pure silver.

From there, the denarius continued its gentle slide, reaching a low-ebb of about 71% near the end of the troubled reign of Commodus (177-192). After that emperor’s murder on New Year’s Eve of 192, the denarius made a slight recovery under Pertinax and Didius Julianus, two emperors who ruled very briefly in 193 during the civil war that followed.

Before that chaotic year had ended, control in Rome was taken by the frontier general Septimius Severus (193-211). Under his otherwise-successful watch, the purity of the denarius dropped to about 57%.

This denarius of Septimius Severus is just slightly more than half silver.

Equally damaging to the long-term health of Rome’s silver coinage was the introduction in late 214 or in 215 of the double-denarius (commonly called an ‘antoninianus’) by Severus’ eldest son, the emperor Caracalla (198-217).

Though apparently tariffed at twice the value of a denarius, the double-denarius only weighed about 1.5 times more than a denarius. This made it an inflationary instrument by nature, for it had less than 70% of the silver contained in two denarius coins that – theoretically – had the same circulation value.

Caracalla denarius struck in 215.

Caracalla double-denarius, also struck in 215.

The double-denarius and denarius were struck concurrently up through 219, after which the double-denarius was abandoned until the civil war of 238. Thereafter, the double-denarius was struck regularly until it ended up supplanting the denarius late in the reign of Gordian III (238-244). From that point onward, silver denarii were rarely produced, and then only as ceremonial coins.

Gordian III denarius struck in 241.

Gordian III double-denarius of 241.

To complicate matters in the study of debasement, there often were differences in purity from one mint to another. For example, in the period 242 to 244, Gordian III’s mint at Rome was striking double-denarii that were about 37% pure, whereas at his mint in Antioch was striking them at an average silver fineness of 43.5%.

Over the next four decades, the purity of imperial silver coinage continued to slide, dropping steadily until it had reached about 41% purity under Trajan Decius (249-251). Soon afterward, under Trebonianus Gallus (251-253) and Aemilian (253), it sank to about 35% pure.

This Aemilian double-denarius, struck in 253, is seemingly is about 35% pure.

The slide picked up momentum as Rome’s economic and military fortunes faded dramatically under the co-emperors Valerian I (253-260) and his son Gallienus (253-268). By the tragic year of 260, when Valerian I was captured by the Persians, the purity of the double-denarius had fallen to as low as 15%.

This double-denarius of Gallienus, struck in 267 or 268, may contain only about 2.5% silver.

However, the worst was yet to come. As crises erupted on all fronts, Gallienus struggled to keep his empire intact. By the time he was murdered in a coup in 268, the double-denarius had slid to a silver content of 5% or less – in some cases dropping to about 2.5%.

As we’ve seen, the saga of Roman Imperial silver from 27 BCE to 268 CE was one of a steady, inexorable decline. In part two of this study, we’ll examine what happened to silver coins during the remaining 200+ years of the Roman Empire.

All images courtesy Classical Numismatic Group (CNG)

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For information on how ancient coins are graded, the following video features an interview with David Vagi: