A legendary ship transporting tons of precious metal capsized in the Mediterranean Sea off the eastern coast of Uluburun in modern-day Turkey more than 2,000 years before the Titanic sank in the North Atlantic Ocean. Since its discovery in 1982, researchers have been examining the artifacts recovered from the Uluburun shipwreck to learn more about the people and the institutions that ruled the Late Period.
Now, a team of scientists, including Michael Frachetti, professor of archaeology in Arts & Sciences at Washington University in St. Louis, have uncovered a surprising finding: small communities of highland pastoralists living in present-day Uzbekistan in Central Asia produced and supplied roughly one-third of the tin found aboard the ship tin that was en route to markets around the Mediterranean to be made into coveted bronze metal.
The study, which was released on November 30, 2022 in Science Advances, was made possible by advancements in geochemical analyses, which allowed researchers to determine with a high degree of certainty that some of the tin came from a prehistoric mine in Uzbekistan, more than 2,000 miles away from Haifa, where the unfortunate ship loaded its cargo.
But how could that be? During this period, small communities of highlander pastoralists far from a major industrial center or empire occupied the mining regions of Central Asia. And the terrain between the two places, which travels through Iran and Mesopotamia, was rocky, making it very challenging to transport tons of heavy metal.
Frachetti and other archaeologists and historians were enlisted to help put the puzzle pieces together. Their research exposed a startlingly intricate supply chain with numerous steps to transport the tin from the little mining community to the Mediterranean market.
“It appears these local miners had access to vast international networks and through overland trade and other forms of connectivity were able to pass this all-important commodity all the way to the Mediterranean,” Frachetti said.
“It’s quite amazing to learn that a culturally diverse, multiregional and multivector system of trade underpinned Eurasian tin exchange during the Late Bronze Age.”
Over the past couple of decades, scientists have collected information about the isotopic composition of tin ore deposits around the world, their ranges and overlaps, and the natural mechanisms by which isotopic compositions were imparted to cassiterite when it formed. We remain in the early stages of such study. I expect that in future years, this ore deposit database will become quite robust, like that of Pb isotopes today, and the method will be used routinely.
Professor Wayne Powell
“Adding to the mystique is the fact that the mining industry appears to have been run by small-scale local communities or free laborers who negotiated this marketplace outside of the control of kings, emperors or other political organizations,” Frachetti said.
“To put it into perspective, this would be the trade equivalent of the entire United States sourcing its energy needs from small backyard oil rigs in central Kansas,” he said.
About the research
The idea of using tin isotopes to determine where metal in archaeological artifacts originates dates to the mid-1990s, according to Wayne Powell, professor of earth and environmental sciences at Brooklyn College and a lead author on the study.
“However, the technologies and methods for analysis were not precise enough to provide clear answers. Only in the last few years have scientists begun using tin isotopes to directly correlate mining sites to assemblages of metal artifacts,” he said.
“Over the past couple of decades, scientists have collected information about the isotopic composition of tin ore deposits around the world, their ranges and overlaps, and the natural mechanisms by which isotopic compositions were imparted to cassiterite when it formed,” Powell said. “We remain in the early stages of such study. I expect that in future years, this ore deposit database will become quite robust, like that of Pb isotopes today, and the method will be used routinely.”
Aslihan K. Yener, a research affiliate at the Institute for the Study of the Ancient World at New York University and a professor emerita of archaeology at the University of Chicago, was one of the early researchers who conducted lead isotope analyses.
In the 1990s, Yener was part of a research team that conducted the first lead isotope analysis of the Uluburun tin. That analysis suggested that the Uluburun tin may have come from two sources the Kestel Mine in Turkey’s Taurus Mountains and some unspecified location in central Asia.
“But this was shrugged off since the analysis was measuring trace lead and not targeting the origin of the tin,” said Yener, who is a co-author of the present study.
Yener also was the first to discover tin in Turkey in the 1980s. She claimed that at the time, the entire academic community was astounded that the first tin bronzes were discovered there, right in front of them.
Some 30 years later, researchers finally have a more definitive answer thanks to the advanced tin isotope analysis techniques: One-third of the tin aboard the Uluburun shipwreck was sourced from the Mušiston mine in Uzbekistan. The remaining two-thirds of the tin derived from the Kestel mine in ancient Anatolia, which is in present-day Turkey.
Findings offer glimpse into life 2,000-plus years ago
By 1500 B.C., bronze was the “high technology” of Eurasia, used for everything from weaponry to luxury items, tools and utensils. Bronze is primarily made from copper and tin. While copper is fairly common and can be found throughout Eurasia, tin is much rarer and only found in specific kinds of geological deposits, Frachetti said.
“Finding tin was a big problem for prehistoric states. And thus, the big question was how these major Bronze Age empires were fueling their vast demand for bronze given the lengths and pains to acquire tin as such a rare commodity. Researchers have tried to explain this for decades,” Frachetti said.
The Uluburun ship yielded the world’s largest Bronze Age collection of raw metals ever found enough copper and tin to produce 11 metric tons of bronze of the highest quality. Had it not been lost to sea, that metal would have been enough to outfit a force of almost 5,000 Bronze Age soldiers with swords, “not to mention a lot of wine jugs,” Frachetti said.
“The current findings illustrate a sophisticated international trade operation that included regional operatives and socially diverse participants who produced and traded essential hard-earth commodities throughout the late Bronze Age political economy from Central Asia to the Mediterranean,” Frachetti said.
Yener said that the mines in ancient Anatolia during the Late Bronze Age were under the influence of the Hittites, an imperial global power that posed a serious danger to Ramses the Great of Egypt. This contrasted with the mines in Uzbekistan, which were situated inside a network of small-scale settlements and migratory pastoralists.
The findings also show that life 2,000-plus years ago was not that different from what it is today.
“With the disruptions due to COVID-19 and the war in Ukraine, we have become aware of how we are reliant on complex supply chains to maintain our economy, military and standard of living,” Powell said. “This is true in prehistory as well. Kingdoms rose and fell, climatic conditions shifted and new peoples migrated across Eurasia, potentially disrupting or redistributing access to tin, which was essential for both weapons and agricultural tools.”
“Using tin isotopes, we can look across each of these archaeologically evident disruptions in society and see connections were severed, maintained or redefined. We already have DNA analysis to show relational connections. Pottery, funerary practices, etc., illustrate the transmission and connectivity of ideas. Now with tin isotopes, we can document the connectivity of long-distance trade networks and their sustainability.”
More clues to explore
The results of the current study resolve long-standing disputes regarding the metal’s origins on the Uluburun shipwreck and the Late Bronze Age exchange of tin between Eurasians and Asia. But there are still more clues to explore.
“After they were mined, the metals were processed for shipping and ultimately melted into standardized shapes known as ingots for transporting. The distinct shapes of the ingots served as calling cards for traders to know from where they originated,” Frachetti said.
The Uluburun ship carried a large number of ingots in the “oxhide” shape, which was previously thought to have originated in Cyprus. But according to the most recent research, the oxhide shape might have come from further east. Frachetti said he and other researchers plan to continue studying the unique shapes of the ingots and how they were used in trade.
