Medieval English Coins Were Made With Melted Byzantine Silver

Researchers have solved the mystery of the silver coin boom that took place around 660 C.E.

Researchers tested 49 medieval coins, finding the older ones were minted from silver Byzantine goods and the newer ones were made of silver mined in western France. The Fitzwilliam Museum / University of Cambridge

In the seventh and eighth centuries C.E., early medieval Brits made a profound change in their spending. The island had long relied on gold for currency—but around 660, its economy was flooded with silver coins.

The influx created an economic boom, stimulating trade and boosting urban development. However, while historians have long studied this surge, the sudden prevalence of silver in medieval Europe has never been explained.

Now, through metallurgical testing, researchers from the University of Cambridge, the University of Oxford and the Vrije Universiteit Amsterdam have determined the source of the precious coins: melted-down Byzantine treasure. The team published its findings this week in the journal Antiquity.

Previously, historians had put forward several theories for the sudden boom—“but there wasn't any hard evidence to tell us one way or the other, so we set out to find it,” as co-author Rory Naismith, a historian at the University of Cambridge, says in a statement.

He adds: “Now we have the first archaeometric confirmation that Byzantine silver was the dominant source behind the great seventh-century surge in minting and trade around the North Sea.”

In the study, researchers tested 49 medieval coins with a technique called “portable laser ablation,” which involves “using a laser to dig into a minute area of the coin—representing a tiny fraction of a millimeter—in order to shed light on its chemical makeup, and ultimately, its origin,” as Newsweek’s Aristos Georgiou writes. They found that 29 of the stash’s older coins (minted between 660 and 750) had isotopic signatures that matched that of third- to seventh-century silver from the Byzantine Empire.

At its peak, the Byzantine Empire stretched from Syria to southern Spain. As the study authors write, its people used silver for both currency and ornamentation. Throughout the empire’s reign, as a wealth of Byzantine silver made its way to Europe, it was hoarded by high-status power brokers, per the Guardian’s Esther Addley.

“Elites in England and Francia were almost certainly sitting on this silver,” says Naismith in the University of Cambridge’s statement. “We have very famous examples of this, [such as] the silver bowls discovered at Sutton Hoo and the ornate silver objects in the Staffordshire Hoard,” referring to two early medieval sites in England.

A silver bowl from the royal early medieval burial site Sutton Hoo The Trustees of the British Museum

According to lead author Jane Kershaw, an archaeologist at the University of Oxford, elite owners of valuable silver items would only melt them down when they really needed the cash.

“This was quantitative easing: Elites were liquidating resources and pouring more and more money into circulation,” says Kershaw in the statement. “It would have had a big impact on people’s lives. There would have been more thinking about money and more activity with money involving a far larger portion of society than before.”

When the researchers tested the stash’s newer coins (minted between 750 and 820), their analysis revealed a different origin. While Byzantine treasure had been the primary source of Britain’s “silver pennies” for nearly a century after 660, its supply started drying up by 750. After that, a silver mine at Melle in France became the dominant source of the precious metal. The researchers argue that the emperor Charlemagne “drove this very sudden and widespread surge in Melle silver as he took increasing control over how and where his kingdom’s coins were made,” per the statement.

The Byzantine origins of Britain’s older silver coins illuminate the interdependent trading networks that drove medieval economies in Europe. As Naismith tells the Guardian, the study “shows that if people in England wanted to have a complex economy with currency, they couldn’t just rely on the resources at home.”

The coins’ newly discovered source—Mediterranean treasure—also sheds light on the economic power of enterprising medieval Brits.

“There wasn’t a Bank of England at this stage,” Naismith tells the Guardian. “If you want some coins, you make some coins. You just need to be someone who’s got the wealth to do it.”

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