Between the 7th and 9th centuries AD, silver coins had a powerful impact on the economy of medieval Europe. During this period there was an increase in the use of pieces in the northwest of the continent, but no one knew exactly where the silver used came from.
Now, a group of researchers from the universities of Oxford, Cambridge and the Vrije Universiteit Amsterdam have analyzed the chemical composition of 49 pieces minted in England, the Netherlands, Belgium and northern France between the years 660 and 820 AD and which are preserved in the Fitzwilliam Museum.
"It has long been speculated that the metal came from Melle in France or an unknown mine or that it could have been melted church silver," explains Rory Naismith, a professor at the University of Cambridge and co-author of the article published in the Antiquity magazine.
Without conclusive evidence, investigators set out to solve the mystery. Experts discovered that the silver used came from two different sources. It all depended on the moment in which the pieces were minted.
Coins dating from the period between 660 and 750 AD. They were made with silver mined in the eastern Mediterranean, in the Byzantine Empire. This metal was probably cast from valuable Byzantine objects, such as the bowls found at Sutton Hoo.
"It's fair to say that this result surprised us," says Dr. Jane Kershaw, lead author of the study. “We know of some surviving Byzantine silver from Anglo-Saxon England – the most famous being from Sutton Hoo – but there must have originally been much larger quantities of Byzantine silver in the British Isles. The connections between Byzantium and England were closer than most people think,” she notes.
"The elites liquidated the silver stored in valuable objects and used it," Kershaw continues, "to make coins that were then widely circulated. It would have had a great impact on the lives of these people, since many more people would have started using minted money and would have thought in terms of monetary values.”
The silver used for later coins, dating from 750 to 820 AD, however came from metal recently mined from Melle, in Aquitaine (France). This change corresponds with the rise of Charlemagne and the rise of the Carolingian Empire in the late 8th and early 9th centuries.
The authors argue that Charlemagne fueled this sudden and widespread rise in Melle silver by taking tighter control over how and where his kingdom's coins were made. A detailed record from the 860s describes Charlemagne's grandson, King Charles the Bald, reforming his money and giving each mint a few pounds of silver as a float to get the process going.
"I strongly suspect that Charlemagne did something similar with Melle's silver," says Professor Naismith. Experts point out that this highlights the efforts made by early medieval rulers to regulate their economies and shows the dependence of England, specifically the kingdom of Mercia, on French silver.
"There was a lot of communication and also tension between Charlemagne and Offa," king of Mercia from 757 until his death in 796, Naismith says. But despite their initial rivalry, England depended on silver from France to produce its own coins.
"Our findings add to a dynamic that England and France have had for a long time." And it also indicates the influence of ordinary Europeans on the politics and economy of the time. "When goods are only found in certain places in limited quantities, questions of power and national interest will always come into play," adds Rory Naismith.
“In the early Middle Ages, this transcended borders and rulers were not the only ones involved. Merchants, churches and other wealthy people were interested. Even so, the fact that the rulers took much more direct measures was something new in this period,” he concludes.
