The Benin Bronzes were made of brass from the Rhineland, according to the surprise findings of a study that throws light on the extensive trade networks involved in slavery.
The famous “bronzes” comprise thousands of artworks, including heads, plaques and figures, produced by the Edo people of Nigeria from the 16th to 19th centuries. Most of those in European and American collections were plundered in 1897 by a British expedition that destroyed Benin City — leading to calls for their return to Africa.
It was previously suspected — but not proved — that the metal in the sculptures was sourced from brass bracelets called “manillas” that were used as currency by European traders. Manillas are depicted on some of the Benin Bronzes and were accepted by the Edo in exchange for slaves and goods such as ivory, pepper and animal skins. In the early 1520s, a 16-year-old female slave cost around 50 manillas in the Kingdom of Benin.
For the new study, published in Plos One, researchers performed chemical analysis on 67 manillas recovered from five Atlantic shipwrecks and three land sites in Europe and Africa. The wrecks included an early 16th-century Flemish ship believed to have sunk while en route to Lisbon; and Whydah Gally, a British slave ship that sank off Cape Cod in 1717 after it was captured by the pirate “Black Sam” Bellamy.
The land sites included that of the African settlement beside the 15th-century Portuguese trading fort at Elmina, Ghana.
The researchers compared the composition of the metals of the different manillas with the Benin Bronzes and European ores. They found a strong similarity between the metal of the Benin Bronzes and that of so-called “tacoais” manillas used in Portuguese trade before the 18th century — indicating that these manillas, specifically, were the principal source of metal for the sculptures. Furthermore, the composition of these manillas was very similar to ores from the German Rhineland.
Tobias Skowronek, of the Technishce Hochschule Georg Agricola, the lead author, said: “The Benin Bronzes are the most famous ancient works of art in all West Africa. Where their brass came from has long been a mystery. Finally, we can prove the totally unexpected: the brass used for the Benin masterpieces, long thought to come from Britain or Flanders, was mined in western Germany. The Rhineland manillas were then shipped more than 6,300km to Benin. This is the first time a scientific link has been made.”
As they explain in the paper: “This study definitively identifies the Rhineland as the principal source of manillas at the opening of the Portuguese [West African] trade. Millions of these artefacts were sent to West Africa where they likely provided the major, virtually the only, source of brass for West African casters between the 15th and the 18th centuries, including serving as the principal metal source of the Benin Bronzes.”
Written sources indicate that huge quantities of “tacoais” manillas were made in the area between Cologne and Aachen — then in the Holy Roman Empire — from the 15th century. Contracts between the region’s brass suppliers and the Portuguese, Dutch and other slave-trading nations also survive. Research by historian Stanley B Alpern has shown that, in 1548, the rich German merchant house of Fugger agreed to provide Portugal with 432 tonnes of cast manillas — almost 1.4 million manillas — in three years, for the Gold Coast trade.
The researchers state that other types of manilla, including manillas made in Britain, were also used extensively in West African trade between the 17th and 20th centuries. However, their chemical analysis of these types, including the manillas found on Wydah Gally, indicates that they were not used by the creators of the Benin Bronzes.
They write: “While early Portuguese-type manillas were an exclusive product of the Rhenish industries, other European manufacturers entered this profitable production sector in the 18th century. These later products are, however, distinct both typologically and metallurgically from the earlier Portuguese manillas. The trace element and lead isotope ratio data presented here indicate that these later manufactures from England and, perhaps, Scandinavia were fabricated using different copper alloys that did not find their way into the crucibles of the Edo casters that produced the Benin Bronzes…”
“Edo metal smiths were likely well aware of the better casting qualities of the Portuguese ‘tacoais’ type manillas, and these were subsequently demanded in trade.”
They state that high levels of lead in early manillas could be interpreted as a deliberate addition to produce an easy-flowing casting brass. They write: “It is astonishing that early 16th-century slave traders apparently recognised African needs for manillas of specific composition.”
The authors observe that manillas were not the only product of the Rhineland brass industry that were traded in West Africa. Finger-thick brass rods known as “Guinea Rods”, and brass vessels such as basins, pots, and kettles were exchanged almost as extensively as manillas along the West African coast.
The Benin Bronzes were made by guilds working for the royal court of the Oba, or king. Many of them were commissioned for the ancestral altars of former Obas and queen mothers. Thousands were looted from the royal palace by members of the 1897 British punitive military expedition that sacked Benin City after an attack on a trade mission. They were acquired by the British Museum and other institutions, some of which have recently pledged to return them to Nigeria.
Last year, Germany signed an agreement to return 1,130 looted Benin artefacts to Nigeria that was welcomed by Unesco for “allowing the African continent to reclaim its heritage”.
The findings come amid increased scrutiny of the far-reaching financial systems and networks that facilitated and profited from the transatlantic slave trade. Between the 16th and 19th centuries, over 12 million enslaved Africans were put on board ships to cross the Atlantic and about two million died on the voyage.
The top image shows Benin Bronzes on display in the British Museum, London. Photo: Alamy