Periodic Reporting for period 1 - ArCAN (An Archaeology of Exchange Networks in Central Africa. The Cases of the Copperbelt and Niari Basin Copper Deposits)
Berichtszeitraum: 2020-10-01 bis 2022-09-30
Before the 20th century, an extensive network of long-distance and regional trade routes crossed Central Africa. The development of these networks and the flow of goods they drained most likely played a major role in the economic and socio-political history of Central Africa but nevertheless remain poorly known, especially for periods predating European contact. ArCAN aimed to reconstruct the history of exchange in the area through multi-evidential sources and a multidisciplinary approach, including archaeology, materials science, historical geography and history. The key approach was to assess the potential of material culture in reconstructing and interpreting exchange networks, starting with the 19th-century regional and long-distance trade and then extending further back in time. The project focused on exchange networks related to copper deposits in the Niari Basin (Republic of Congo) and the Copperbelt (southern Democratic Republic of Congo and northern Zambia). Copper was a valuable metal and was exchanged during the entire second millennium over long distances. The value of copper and its durability in the archaeological record offers a good gateway to explore regional and long-distance exchange networks over time. It furthermore allows to gain more insight in the role of valuable materials and their producing communities in the building and dynamics of the trade networks. The goal was also to document the processes at work in the creation and management of long-distance exchange networks by specifying the relative contributions of local and regional exchange, local communities and larger socio-political spaces, and the impact of natural features on the physical layout of networks. The solid empirical ground gained would allow feeding general theoretical and methodological reflections for further studies on ancient interaction in places where material culture is the only available record to document the past.
ArCAN has been ended prematurely as ER obtained a long-term position. Research therefore mainly focused on the late 19th-century trade in west Central Africa. Historians use the concept of 'Great Congo Trade' to describe the complex set of regional and local networks that allowed exchange of goods between the coast and inland areas along the Congo River as far as the Kisangani area. Both copper and brass circulated in the late 19th century networks. The copper mainly originated from the Niari Basin– though other deposits may have supplied the area as well – and the brass was imported from Europe through trade from the coastal factories to inland areas.
The work conducted during the action revolved around three main questions. The first concerned the reconstruction of the layout of the regional and local trade from and to the Niari Basin in the late 19th century. The second was on how to get more insight into the mechanisms underlying these networks and the role of the copper-producing communities and of copper and brass as such in the Great Congo Trade. A last focus was on how to follow the flow of copper and brass and to assess their respective importance in the trade.
Due to the COVID-19 crisis, the work has been mainly conducted remotely. In addition to early colonial accounts and maps, the collections of copper objects and of related archives from the Royal Museum for Central Africa (Belgium) and the Museum of Anthropology and Archaeology, University of Cambridge have been examined in order to identify objects that were used as currency or likely to inform on the circulation of copper and brass.
In addition, preliminary portable X-ray fluorescence (pXRF) analyses have been conducted on 51 copper objects at the Museum of Anthropology and Archaeology. Partly collected by missionaries in the early times of the colonisation along the Congo River, precise contextual data are however lacking. These objects nevertheless provide a glimpse of the metal in circulation in the riverine area of the Great Congo Trade upstream of the Malebo Pool, when indigenous trade networks were still in place.
The work conducted during the action revolved around three main questions. The first concerned the reconstruction of the layout of the regional and local trade from and to the Niari Basin in the late 19th century. The second was on how to get more insight into the mechanisms underlying these networks and the role of the copper-producing communities and of copper and brass as such in the Great Congo Trade. A last focus was on how to follow the flow of copper and brass and to assess their respective importance in the trade.
Due to the COVID-19 crisis, the work has been mainly conducted remotely. In addition to early colonial accounts and maps, the collections of copper objects and of related archives from the Royal Museum for Central Africa (Belgium) and the Museum of Anthropology and Archaeology, University of Cambridge have been examined in order to identify objects that were used as currency or likely to inform on the circulation of copper and brass.
In addition, preliminary portable X-ray fluorescence (pXRF) analyses have been conducted on 51 copper objects at the Museum of Anthropology and Archaeology. Partly collected by missionaries in the early times of the colonisation along the Congo River, precise contextual data are however lacking. These objects nevertheless provide a glimpse of the metal in circulation in the riverine area of the Great Congo Trade upstream of the Malebo Pool, when indigenous trade networks were still in place.
The combination of archival and collection-based research with laboratory analyses allows to meet some of the initial objectives of the project. Copper and brass were not the primary purpose of the trade and local production seems to have been a side activity. They had nevertheless a widespread use in the Great Congo Trade, displaying a diversity of shape and value. Copper from the Niari Basin was primarily traded through the local network before reaching regional trade routes where they were traded alongside brass imported from the coast.
The exploratory pXRF analyses allowed to outline that even though brass was dominant among the objects analysed, it did not fully replace locally produced copper at the end of the 19th century as the assumption has been for a long time. Thanks to a characteristic chemical composition, copper objects likely to originate from the Niari Basin have been indeed identified in distant areas along the Upper Congo River as late as the first decades of the 20th century. In addition, by comparing the composition of brass rods imported from Europe – the main raw material for making brass objects - with the locally cast objects, the level of recycling along the trade networks can be assessed because the brass is losing Zn at every melt. The limited identified number of objects made of recycled metal all comes from peripheral areas. These objects would reflect the higher number of intermediaries between the source of metal and the final object as suggested by historical sources while riverine groups along the Congo River, the main trade axe, had a more direct access to new copper or brass ingots.
The organisational structure of the Great Congo trade may explain the widespread use of copper and brass. While some nodes attracted a larger flow of goods because of their strategic position, the complex interaction of local and regional networks made every portion of the route important. Negotiation at the different interfaces was crucial for the proper running of trade. Even though natural features seem to have influenced the general layout of the routes, local actors played an as important role in the actual itineraries of the trade, being able to reshape them at the local level. In such a set of complex and heterogenous networks, the material properties of brass and copper allowed them to be easily transformed in response to the local demands. They could then cross the many thresholds of the Great Congo Trade by being endowed with new attributes, facilitating the exchange at the interface between different socio-economic or political spheres.
The results illustrate the importance of investigating trade at a more local scale to understand the dynamic of exchange over long distances in the Congo Basin and set the ground for further research on trade for earlier periods.
The exploratory pXRF analyses allowed to outline that even though brass was dominant among the objects analysed, it did not fully replace locally produced copper at the end of the 19th century as the assumption has been for a long time. Thanks to a characteristic chemical composition, copper objects likely to originate from the Niari Basin have been indeed identified in distant areas along the Upper Congo River as late as the first decades of the 20th century. In addition, by comparing the composition of brass rods imported from Europe – the main raw material for making brass objects - with the locally cast objects, the level of recycling along the trade networks can be assessed because the brass is losing Zn at every melt. The limited identified number of objects made of recycled metal all comes from peripheral areas. These objects would reflect the higher number of intermediaries between the source of metal and the final object as suggested by historical sources while riverine groups along the Congo River, the main trade axe, had a more direct access to new copper or brass ingots.
The organisational structure of the Great Congo trade may explain the widespread use of copper and brass. While some nodes attracted a larger flow of goods because of their strategic position, the complex interaction of local and regional networks made every portion of the route important. Negotiation at the different interfaces was crucial for the proper running of trade. Even though natural features seem to have influenced the general layout of the routes, local actors played an as important role in the actual itineraries of the trade, being able to reshape them at the local level. In such a set of complex and heterogenous networks, the material properties of brass and copper allowed them to be easily transformed in response to the local demands. They could then cross the many thresholds of the Great Congo Trade by being endowed with new attributes, facilitating the exchange at the interface between different socio-economic or political spheres.
The results illustrate the importance of investigating trade at a more local scale to understand the dynamic of exchange over long distances in the Congo Basin and set the ground for further research on trade for earlier periods.