The mystery surrounding the origin of the tin used in the Bronze Age has baffled archaeometallurgists for over a century. Bronze, a crucial alloy made from copper and tin, was the material of choice for crafting a wide array of items during this era, including swords, helmets, bracelets, plates, and pitchers.
Unraveling the source of this tin holds the promise of offering profound insights into early trade networks that connected regions as diverse as Central Asia, Mesopotamia, North Africa, the Levant, and Europe. This early form of globalization had a transformative impact on the ancient world.
The key to solving this age-old puzzle might lie within the cargo of a merchant ship that sank around 1320 BCE off the western coast of Turkey near Uluburun. In 1982, divers discovered this shipwreck, and underwater archaeologists subsequently recovered its cargo. Among the treasures, they found an astonishing 10 tons of copper ingots and one ton of tin ingots, a discovery of unprecedented scale for the Bronze Age.
Ernst Pernicka, a senior professor at the University of Tübingen and the scientific director of the Curt Engelhorn Center for Archaeometry (CEZA) at the Reiss-Engelhorn Museum in Mannheim, remains optimistic about solving the enigma. He notes that even four decades after the Uluburun find, the tin’s origin continues to elude us, but progress is being made through innovative methods.
In a recently published study in the journal Frontiers in Earth Science, Dr. Daniel Berger and his team at CEZA challenge the findings of a research team led by Professor Wayne Powell of Brooklyn College in New York. Powell’s team had claimed, in a November 2022 article in the journal Science Advances, that they had definitively identified the origin of the tin from the Uluburun shipwreck.
According to Powell’s team, a significant portion of the tin originated from the Mushiston tin deposit in northwestern Tajikistan, along with contributions from two mines in the Taurus Mountains near the present-day Turkish-Syrian border. They arrived at this conclusion by analyzing 105 tin ingots from the wreck, assessing their chemical and isotopic signatures. The isotope ratios of tin and lead, along with tellurium levels, provided clues about the tin’s source.
However, Berger and his colleagues refute this assertion, stating that “the data does not support this interpretation and does not allow for a clear conclusion.” Berger extensively reviewed chemical and isotopic analyses from previous studies and cross-referenced them with Powell’s dataset.
Based on isotopic ratios and chemical properties, Berger suggests that the tin may have originated from Cornwall in Britain or possibly the Saxon-Bohemian Erzgebirge or the Iberian Peninsula. He emphasizes the need for additional samples and analyses of ores from European and Asian tin deposits to reach a definitive conclusion.
The Bronze Age, spanning from the late fourth millennium to the early first millennium BCE, varied in its beginnings and endings depending on the geographical region. Bronze, a copper-tin alloy in a 9:1 ratio, offered superior hardness compared to pure copper. While copper ores were plentiful across Eurasia and Africa, tin deposits accessible during the Bronze Age were limited to a few regions in Central Asia, Iran, and Europe.
What makes this situation intriguing is that some of the earliest bronze artifacts have been discovered in the Mesopotamian city-states of the Tigris-Euphrates river system, an area devoid of tin deposits. This indicates that tin had to be procured through extensive long-distance trade networks.
Archaeological evidence points to a thriving economic connection between the British Isles, Central Europe, and the Mediterranean during the Bronze Age. This connection was facilitated by trade routes along the Danube, Rhine, and Rhône rivers, as well as maritime routes. For instance, the presence of amber beads in the Uluburun wreck suggests the existence of north-south trade routes.
The adoption of standardized weights, which had spread from Egypt and Mesopotamia through Syria, Anatolia, the Aegean, and across the Alps into Central Europe by the second millennium BCE, further eased trade. During the time of the Uluburun shipwreck, no evidence of weight systems or established trade links to Europe and the Eastern Mediterranean can be found in Central Asia. This reinforces the likelihood that the tin primarily came from western sources.