High tech coin research reveals metal source

The silver composition of ancient Roman coins may indicate the source of that silver.

Coins may be objects to be viewed and enjoyed by collectors. To archaeologists and researchers, they are artifacts to be studied to draw conclusions regarding their contemporary function and about the society in which they were made.

This research has been going high tech for some time. A recent application of geochemical analysis techniques has concluded that ancient coins of Carthage issued in the name of General Hannibal Barca were struck using silver mined in what today is Spain.

Hannibal (247-182 B.C.E.) occupied parts of Italy for 15 years. He was eventually defeated at the Battle of Zama by Roman General Scipio Africanus, who had studied Hannibal’s tactics. Hannibal later held the office of shophet in Carthage, enacting financial reforms through which indemnities were paid to Rome.

Hannibal left Carthage to advise Seleucid King Antiochus III in his unsuccessful war against Rome. Still later, Hannibal lived in Armenia, then in Bithynia, where he was betrayed. Hannibal committed suicide rather than be taken prisoner by the Romans.

It is Hannibal’s Second Punic War (against Rome) silver coinage that is the subject of mass spectrometry by Goethe University in Frankfurt, Germany, with Warwick University in Coventry, England.

The study concluded that Hannibal’s defeat by Rome led to what is now a “tangible record” of wealth across what would become the Roman Empire, traceable to the silver mines in Spain. The Second Punic War led to Rome capturing the Iberian Peninsula silver mines about 211 B.C.E. Scientists recently analyzed 70 Roman silver coins of the 310 to 301 B.C.E. range to the 101 B.C.E. period using mass spectrometry. They concluded that most of the coins struck after 209 B.C.E. have lead isotopic signatures identifying southeast and southwest Spain as the place of origin for their metal composition.

The findings were presented at the recent Goldschmidt Conference in Paris. The conference is a primary meeting for presentation and exchange of scientific ideas in geochemistry. The conference is owned by the Geochemical Society and European Association of Geochemistry.

According to the paper presented, the changing origin of the bullion used to make coins is mirrored by differing ratios of the lead isotopes 208Pb, 207Pb, 206Pb and 204Pb. These isotopes serve as geological clocks, recording the formation age of the silver ores.

Dr. Katrin Westner of Goethe University is a co-leader of the coinage study. According to Westner, “Before the war we find that the Roman coins are made of silver from the same sources as the coinage issued by Greek cities in Italy and Sicily. In other words the lead isotope signatures of the coins correspond to those of silver ores and metallurgical products from the Aegean region.”

Westner continued, “But the defeat of Carthage led to huge reparation payments to Rome, as well as Rome gaining high amounts of booty and ownership of the rich Spanish silver mines. From 209 B.C. we see that the majority of Roman coins show geochemical signatures typical for Iberian silver. This massive influx of Iberian silver significantly changed Rome’s economy, allowing it to become the superpower of its day.

“We know this from the histories of Livy and Polybius and others, but our work gives contemporary scientific proof of the rise of Rome. What our work shows is that the defeat of Hannibal and the rise of Rome is written in the coins of the Roman Empire.”

Kevin Butcher is a professor at the Department of Classics and Ancient History at Warwick University. Butcher said, “This research demonstrates how scientific analysis of ancient coins can make a significant contribution to historical research. It allows what was previously speculation about the importance of Spanish silver for the coinage of Rome to be placed on a firm foundation.”