Where Bronze Age civilizations got large amounts of tin, a scarce metal, to mix with copper into the era’s namesake gold-colored metal has long puzzled archaeologists.
A big part of the answer lies in Cornwall and Devon, two counties in southwestern England, a new study concludes. Farming communities began mining large tin ore deposits there around 4,200 years ago, say archaeometallurgist Alan Williams of Durham University in England and his colleagues.
That metallic harvest spread through trade routes, supplying societies in northern and central Europe around 3,800 years ago and Eastern Mediterranean societies about 3,400 years ago, the scientists report May 6 in Antiquity. Archaeologists date the Bronze Age to between roughly 5,000 and 3,000 years ago.
“Tin from southwestern Britain was a major commodity source and did, we believe, enable the full transition of Eastern Mediterranean civilizations from copper to bronze use,” says Benjamin Roberts, a Durham archaeometallurgist and study coauthor.
Contrary to an earlier investigation, Williams’ group concludes that trade in British tin greatly exceeded trade in tin from Central Asian sources as the Bronze Age played out. A tidal island in Cornwall, Saint Michael’s Mount, served as an ancient tin trading center, the researchers suspect.
Their argument favoring British tin sources rests on analyses of trace elements and different forms, or isotopes, of lead and tin in tin ore samples from Cornwall and Devon.
Chemical signatures of Cornwall and Devon tin appear in shaped pieces of tin, called ingots, previously retrieved from a 3,000-year-old shipwreck near southwestern England and two 3,300-year-old shipwrecks off Israel’s coast, the scientists say. Tin ingots from a shipwreck off France’s southwest coast — dated to around 2,600 years ago, after the Bronze Age ended — also display British origins.
Geoarchaeologist Wayne Powell of Brooklyn College in New York City led the previous study, which traced tin from the 3,300-year-old Uluburun shipwreck off Turkey’s coast to Central Asian sources. Powell welcomes the new findings but says ancient texts and chemical analyses of bronze objects still point to Central Asia as a prime tin source throughout the Bronze Age. That tin, he says, passed along trade routes into what is now Iraq and then west to modern-day Turkey, where it was distributed to Eastern Mediterranean societies.
But Williams notes that high lead levels in Uluburun ingots indicate that lead was added to tin somewhere along a trade route, complicating attempts to identify where the Uluburun metal originated.
No comparable trace element and lead isotope data exist for two large Central Asian tin ore sites. Current evidence suggests that by around 3,500 years ago, those locations supplied tin mainly to bronze-producing societies in East Asia, providing only minor amounts to the Eastern Mediterranean, Williams’ team contends.
Powell disagrees. Numerous ancient tin mines existed in Central Asia, including at least 28 recently documented by Russian archaeologists in Kazakhstan, he says. Bronze items found at Eastern Mediterranean sites dating from around 4,000 to 3,600 years ago display tin isotope values characteristic of Central Asian sources.
Over the subsequent centuries, surviving bronze items in the Eastern Mediterranean contained tin from a mix of European and Central Asian sources, Powell says. But Central Asian suppliers still dominated, partly for political reasons. Sea currents and winds forced trading ships from Britain and other western ports to travel along the southeastern Mediterranean coast, he explains, where Late Bronze Age warfare between Egyptians and Hittites temporarily blocked trade.
Researchers on both sides of this debate agree that much remains unknown about Bronze Age trade networks that carried tin and other goods across vast stretches of land and sea. “Every available tin source was exploited to meet the demand for tin by the great population centers of the ancient world,” Powell says.
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