Tiny glass beads discovered in mountain caves about 25 miles from the shores of Lake Malawi in east-central Africa provide evidence that European trade in the continent’s hinterland was built on indigenous coastal-inland trade routes that had existed for centuries, a study published co-authored by Yale anthropologist Jessica Thompson.
The beads are also artefacts from the 19th centuryth In the mid-20th century, when increased European political and economic interest in the region affected trade between Indian Ocean traders and communities in interior Africa, Thompson said.
The study, published in the journal African Archaeological Review, is based on a collection of 29 glass beads excavated from 2016 to 2019 at three sites in northern Malawi’s Kasitu Valley, more than 400 miles from the east coast. The elemental composition of the beads was revealed that all but one were made in Europe using glass recipes that were in vogue around the mid-19th centuryth Century. The exception had a 15th-century composition typical of South Asian-made glass beadsth until the 17thth Century.
The origin of the beads indicates that the people of the region traded either directly or indirectly with Europeans before the latter group had a presence in what is now Malawi in the second half of the 19th centuryth Century. This trade was most likely associated with increased trade in raw materials such as copal gum – a resin used in the lacquer industry – and ivory, which was valued in Europe and North America. It also likely involved the capture and transportation of enslaved people, who were taken in chains to spice plantations on Zanzibar and other Indian Ocean islands, Thompson said.
“It’s a dark story,” said Thompson, an assistant professor of anthropology in Yale’s Department of Arts and Sciences and the paper’s senior writer. “Traders in the Indian Ocean had access to European goods like these little pearls, which they could barter for items in high demand in distant locations — a history of exploitation deep in Africa that continues to this day. And in the mid-19th century there was still a slave trade throughout East Africa that would continue for several decades.”
Thompson is a paleoanthropologist whose research typically involves much older groups of people. But when she and colleagues searched for Stone Age artifacts at sites in Malawi, glass beads turned up in her 1-millimeter sieves. (All but one of the beads are less than 5 millimeters in diameter. The smallest were less than 2 millimeters in diameter.)
“Some were so tiny that we didn’t know we were looking at pearls when we first found them,” she said. “They just look like little brightly colored spots.”
Thompson and her other co-authors teamed up with Laure Dussubieux, a senior research scientist at the Field Museum in Chicago, who analyzed the composition of the beads using a technique called inductively coupled plasma laser ablation mass spectrometry. Essentially, the beads were zapped with a high-energy laser to determine their elemental composition without damaging them, Thompson said.
It was the first time this technique was applied to glass beads unearthed in Malawi, where thousands of glass beads have been discovered at dozens of sites since 1966.
The researchers used the chemical composition of the beads to identify their origin. For example, five red-on-white beads in the study contained high levels of arsenic, which was used in the 19th centuryth Century to make glass opaque. According to the study, these beads were probably made in Venice, which was the center of the European beading industry in the 19th century. They were made around the time the Scottish missionary David Livingstone was making maps of the African interior and encouraging the people of Britain to take a greater interest in east-central Africa. (The British eventually established a government in Malawi, which became an independent country in 1964).
A single bead obtained from one of the sites was the only non-European specimen in the collection. Its composition is consistent with pearls mined in Chaul, a former city on the Indian coast of Maharashtra, since the 15th centuryth until the 17thth The researchers concluded that it reached the East African interior in the 19th century, meaning it likely entered the East African interior hundreds of years before European pearls.
Two cowrie shells, abundant in the Indian Ocean and used for currency and jewelry, were discovered at a fourth site that contained no glass beads. Radiocarbon dating found the shells to be between 1,341 and 1,150 years old, suggesting the glass beads of European and Indian origin made their way to inland communities via long-established trade networks, Thompson said.
“This tells you that people were already trading via very complex routes from the Indian Ocean, over mountains and around lakes to inland communities at least 1,000 years before Europeans began to record their experiences in the region,” she said. “Newcomers to Africa used trade routes created by long-term indigenous interactions.”
“It’s not just a story of Europeans arriving and distributing their goods to people in interior Africa,” she added. “The people who lived there traded goods from the Indian Ocean in well-established and productive ways for centuries. Our work shows how archeology and artifacts can reveal important information that would remain hidden if reliance was placed solely on written accounts.”
Menno Welling from the University of the Arts Amsterdam and Potiphar Kaliba from the Department of Museums and Monuments in Malawi are co-authors of the study.