The beginning of the Iron Age south of the Congo rainforest: the first archaeological investigations around Idiofa (Congo), c. 146 BC – AD 1648

ABSTRACT

Archaeological investigations of the Idiofa region in the Kwilu Province of the Democratic Republic of Congo have yielded the earliest evidence for iron production, combined with ceramics and lithic artefacts, south of the Congo rainforest during the second century BC. Palaeoecological data show that the producers of this industry did not settle in open grasslands but in a habitat where the forests had started to undergo climate-induced degradation before their arrival. The Early Iron Age at Idiofa continues until the third century AD and is followed by a long hiatus that was not driven by climate change until the fifteenth century. Later Iron Age (LIA) pottery in the area, which dates to c. 1487–1648, is markedly distinct from that of the EIA in vessel forms, size, recipe and decoration. EIA pottery from Idiofa resembles most closely slightly younger Kay Ladio pottery (c. cal. AD 30–475) from the Lower Congo region further west, which is also associated with the first metallurgy there. Idiofa’s LIA pottery is indicative of a fifteenth- through seventeenth-century exchange network between the Kamtsha and Kasai Rivers. These shifting dynamics in pottery production are reflected in the region’s linguistic stratigraphy, which may contribute to the interdisciplinary reconstruction of the history of ancestral Bantu speakers south of the rainforest.

RÉSUMÉ

Les recherches archéologiques dans la région d’Idiofa, dans la province du Kwilu, en République Démocratique du Congo, ont mené à la découverte des premières traces de la production du fer au sud de la forêt du bassin du Congo. Elles remontent au cours du deuxième siècle avant J.-C et sont associées à la céramique et aussi aux vestiges lithiques. Les données paléoécologiques montrent que les producteurs de cette industrie ne se sont pas installés dans des savanes ouvertes, mais dans un habitat dont les forêts avaient commencé à se dégrader avant leur arrivée, suite aux changements climatiques. L’Âge du Fer ancien à Idiofa continue jusqu’au troisième siècle de notre ère. Après cela un long hiatus non lié au changement climatique perdure jusqu’au quinzième siècle. La poterie de l’Âge du Fer récent (c. 1487–1648 ap. J.-C.) se distingue nettement de celle de l'Âge du Fer ancien par la forme, la taille, la composition et la décoration. La poterie de l’Âge du Fer ancien d'Idiofa ressemble davantage à la poterie Kay Ladio (c. 30–475 ap. J.-C.) de la région du Bas-Congo, située plus à l’ouest et de date un peu plus récente. Elle est également associée à la métallurgie la plus ancienne de cette région. La poterie d’Idiofa de l’Âge du Fer récent est révélatrice d’un réseau d’échange qui s’étendaient entre les rivières Kamtsha et Kasai du quinzième au dix-septième siècles de notre ère. Ces dynamiques en mutation dans la production de la poterie se reflètent dans la stratigraphie linguistique de la région, ce qui est pertinent pour la reconstruction interdisciplinaire de l’histoire des communautés bantouphones ancestrales au sud de la forêt tropicale.

KEYWORDS:

• Iron Age
• Democratic Republic of the Congo
• iron production
• ceramic analysis
• lithic artefacts
• palaeoecology

Acknowledgements

We thank Prof. Placide Mumbembele Sanger, the then General Director of the Institut des Musées Nationaux du Congo (IMNC) and his successor M. Jean-Pierre Bokole Ompoka, as well as the IMNC staff, for all their support. We also extend a special thank you to Isidore Nkanu, our chef de fouilles, and to Prof. Léon Mundeke (UNIKIN), who participated in the 2019 BantuFirst fieldwork mission in Idiofa. Thank you also to Chad Yost and Samuel Bodé. The project would not be possible without the assistance of our full team and local collaborators. The 2019 mission was carried out under the Arrêté ministériel n°091/CAB/MIN/CA/PKB/2018. This work was supported by the European Research Council under Consolidator’s Grant 724275.

Additional information

Notes on contributors

Peter R. Coutros

Peter R. Coutros has been a postdoctoral researcher at Ghent University with the BantuFirst project since 2021. He received his PhD in anthropology from Yale University (2017) where he directed the DARE project, focused on the reconstruction of the Late Stone Age/Early Iron Age socio-ecological landscape of the Diallowali site system in northern Senegal. His research interests include ceramic seriation, social and technological change and the social impacts of climate change. In addition to Congo-Kinshasa and Senegal, he has undertaken research in Mali, Mauritania, Kenya, Madagascar, Peru, Guatemala and Mongolia.

Igor Matonda

Igor Matonda Sakala is an Associate Professor at the University of Kinshasa in the Department of Historical Sciences. He holds a joint PhD in African Languages and Cultures from Ghent University (2017) and History, Art History and Archaeology from Brussels University (2017). His dissertation focused on the Inkisi Valley in the era of the Kongo kingdom using historical, archaeological and linguistic data. His teaching and research focus on African precolonial and colonial history, the early and more recent settlement and population history of the Congo, demographic history, historical archaeology and ceramic traditions.

Jessamy H. Doman

Jessamy H. Doman is a BantuFirst postdoctoral researcher focused on reconstructing palaeoenvironments. She directed the Baringo Palaeontological Research Project as part of her PhD (Yale University, 2017), resulting in a new understanding of the environmental backdrop to Miocene-Pliocene faunal and human evolution in Africa and the development of novel methods in palaeoecological reconstruction.

Sara Pacchiarotti

Sara Pacchiarotti is Associate Professor in Linguistics at Ghent University where she will be leading the interdisciplinary ERC-funded project ‘The Congo-Ubangi watershed: an interdisciplinary approach to the genesis of a linguistic accretion zone in Central Africa (CongUbangi)’. She is interested in how and why language changes over time and has worked on several Niger-Congo languages in West and Central Africa Chibchan languages in Costa Rica.

Isis Mesfin

Isis Mesfin is an archaeologist and postdoctoral researcher with the Fondation Fyssen at the Museu Nacional de Arqueologia de Benguela, Angola. She completed her PhD in 2021 at the Muséum National d’Histoire Naturelle in Paris on early hominin dispersal along the southern African Atlantic coast during the Early and Middle Pleistocene. Her research focuses on techno-cultural dynamics and evolution in Central Africa and the origin and adaptation of early hominins in the coastal landscapes of Africa.

Koen Bostoen

Koen Bostoen is Professor of African Linguistics and Swahili at Ghent University. His research focuses on Bantu languages and interdisciplinary African history studies. He obtained an ERC Starting Grant for the KongoKing project (2012-2016) and an ERC Consolidator’s Grant for the BantuFirst project (2018-2023) and is the author or editor of several books on Kongo history and Bantu languages.