From the Study:

"Byzantine bullion fuelled Europe’s revolutionary adoption of silver coins in the mid-7th century, only to be overtaken by silver from a mine in Charlemagne’s Francia a century later, new tests reveal.

"Between 660 and 750 AD, Anglo-Saxon England witnessed a profound revival in trade involving a dramatic surge in the use of silver coins, breaking from a reliance on gold. Around 7,000 of these silver ‘pennies’ have been recorded, a huge number, about as many as we have for the rest of the entire Anglo-Saxon period (5th century – 1066).

"In research published today in Antiquity, an international team of researchers led by Dr Jane Kershaw has solved the mystery of where the silver in these Anglo-Saxon coins came from by analysing the make-up of coins held by the Fitzwilliam Museum in Cambridge.

"49 coins from Fitzwilliam’s collections (dating from 660 to 820 AD) were analysed for trace element and lead isotope analysis. A portable laser ablation technique ensured minimally invasive sampling of the coins whilst still achieving the high precision results of more traditional methods in which physical samples of silver are taken.

"While the coins mostly contained silver, the proportion of gold, bismuth and other elements in them guided the researchers to the silver’s previously unknown origins. Different ratios of lead isotopes in the silver coins provided further clues."

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