A recent article about Rome recycling its coinage brought home to me the idea that modern Western society didn’t invent re-cycling, as many of us are prone to think. Over history, coinage has been recycled, churches have been recycled, even empires have been recycled, and ideas have certainly been recycled and repurposed.
Silver was the basis of Roman coinage for over 450 years, and appetite for the metal prompted many of Rome’s conquests. Major silver mines in Iberia and France were jealously protected by Roman armies, and Roman governors were appointed to control those mines. From time to time major wars did disrupt the silver supply, but that didn’t seem to affect the silver content of the coinage, or the availability of coins.
It has been a point of contention among historians why the coinage wasn’t affected by restrictions to silver mines access, but a recent study by a group at the University of Liverpool have answered that question with evidence from the most unlikely of places……Greenland.
Roman armies never made it as far as Greenland, and it’s unlikely that Rome even knew the territory existed. However, Greenland’s ice sheets have preserved traces of atmospheric lead, emitted in Europe and North Africa as part of the silver-making process. Roman silver coins were ubiquitous during the days of their empire and fluctuations of lead levels in the atmosphere, and subsequently in the ice-sheets, serve as a proxy for Roman money supply. I’m constantly amazed how scientists come up with these connections.
Dr. Jonathan Wood, and his team from the University of Liverpool, used the presence of gold in the silver as a measure of what might have happened when silver supplies were restricted: Trace amounts of gold are always found in silver deposits. The percentage of gold in silver deposits varies, depending on location, and some of the highest are found in Iberia, where Rome had significant mining operations. Dr. Wood and his team discovered that around 120BC the level of gold in some Roman coinage dropped significantly, and they wondered why.
It could have been a result of a new source/mine for the silver but there were no increases in the Greenland ice-sheet levels of lead, which would have indicated new mining operations.
Studies of the ice sheets have also shown that silver production was significantly affected by wars during the Roman era, and that should have resulted in less coinage in circulation. However, there appears to be little evidence of this paucity. The number of coins in circulation was fairly constant. So how did the Romans sustain their silver supply for coins when their sources of silver were compromised by war?
There are several possible answers. One method that was used throughout antiquity to prop up coinage, and economies, was debasing the currency by adding another, cheaper, metal to the coinage – copper was a common additive. However, tests on Roman coinage over long periods of time have indicated that the percentage of silver rarely fell below 95%. This would indicate that debasing of the coinage was not a common occurrence.
Dr. Wood speculates that the Romans may have turned to recycling to solve the problem of a silver shortage. AND, not only recycling of their own coins but also mixing those coins with recycled coinage from other sources. The Roman Empire was extensive, and Roman armies sent much of their “booty” back to the Capital, which including “liberated” local coinage. If that “liberated” coinage was melted down and mixed with old Roman coinage, it could account for the drop in gold content. The recycled coins might well have the same overall silver content but the gold content from “foreign/inferior” currencies could change. Sounds plausible!
There is one concrete example that could back up Wood’s theory. When Julius Cesar returned to Rome after his successful invasion of Gaul, he and his army were laden with “booty”. The study of Roman coinage minted after that event shows a significant drop in the gold content.
It is also interesting to note that that new coinage was used by Cesar to fund his civil war, which ultimately resulted in the establishment of his adopted son, Cesar Augustus, as the first Roman Emperor, and the demise of the republic.
It is therefore possible to speculate that this connection between gold levels in silver Roman coins, trace elements of lead in Greenland ice-sheets and Roman history, could result in a whole new area of study for the academic world. As I said, amazing connections.