Early western European coins’ Byzantine origins

About 200 years after the fall of the Roman Empire, western Europe started making thousands of silver coins, signaling a transformation in the early medieval economy. A new chemical analysis of currency from seventh and eighth centuries England, France, and the Netherlands suggests that this boom in coin production may have started with silver from the Byzantine Empire in the eastern Mediterranean (Antiquity 2024, DOI: 10.15184/aqy.2024.33).

“It’s really interesting when you have the sudden appearance of silver when there has been no silver [coinage] beforehand, to ask where that comes from,” says Jane Kershaw, an archaeologist at the University of Oxford who led the study.

Kershaw and collaborators at the University of Cambridge and the Free University of Amsterdam used a technique called portable laser ablation to remove tiny samples of metal from 49 early medieval coins from the Fitzwilliam Museum in Cambridge, England. The researchers carried out the minimally destructive sample collection process at the museum in Cambridge, and then sent the samples to Amsterdam to be analyzed by inductively coupled plasma mass spectrometry.

The researchers looked at the coins’ trace metal content as well as the ratio of lead isotopes in the metal. Kershaw says she had expected all the coins to have been made from silver mined in what is now France, in Melle. The coins made after 750 CE were made from Melle silver, but the 29 oldest coins were clearly from elsewhere, she says. They all had a higher fraction of trace gold and larger amounts of heavier lead isotopes, which suggested that those older coins came from the same silver stock.

The older coins’ composition was distinct from that of silver mined elsewhere in western Europe, recycled Roman silver, and silver from the Middle East. Kershaw says it was surprising to find that the composition matched that of Byzantine silver, because there isn’t much other evidence of trade between the Byzantine Empire and western Europe at the time.

“Researchers often want an easy answer” to provenance questions, says Nicole Little, an analytical scientist at the Smithsonian Institution’s Museum Conservation Institute. Scientists often hope that a single technique or elemental signature revealed all the answers—but artifacts can have complicated histories. Little says Kershaw and her colleagues “did a good job capturing the nuances of analytical chemistry” by collecting both trace element and isotope data to understand the coins’ origins.

Old coinage and other silver artifacts can reveal a lot about history, Kershaw says. “It’s in museum collections. There’s a lot of it. Come on, people, analyze it!”