Natalie Mitchell

Iron Metallurgy in Africa

Origins

The origin of iron metallurgy in Africa is hotly disputed by archaeologists. The first evidence for iron in Africa dates back as far as the second millennium BC. The vast scale of the continent, accessibility, political and cultural barriers have caused difficulties in finding a good database of evidence to help diagnose when and where origins lie. It has now been recognised that trying to put the origins in some kind of chronological order is not currently possible with the archaeological evidence available and controversial when attempted.

Archaeologists hold several standpoints on the origins of iron production in Africa:

1. Indigenous Invention

Some archaeologists believe that it was indigenously invented without influence from outside countries already practising production. It is possible that the process was an innovation of the smelting techniques already used in Africa to make copper. Iron oxides were used as a flux in the copper smelting process and so with some experimentation the process could have resulted in accidental production of iron, which could have then been developed into purely iron smelting. However although copper was smelted in some regions before iron, evidence for copper production is relatively low due to the poor preservation of copper production techniques. If earlier evidence of copper smelting could be found it would strongly support the argument. The only real evidence from copper smelting is the remaining slag. However in the field this can often be confused for iron slag without metallographic analysis.

2. Diffusion from surrounding continents

The second argument is that techniques were brought to the continent by surrounding countries by diffusion. Proposed routes by the diffusion process either could be running south to West from Meroe on the Nubian Isle (Childs et al. 2005, pg 278). Or some believe it came on a path from Egypt which dispersed the methods from the North to the Sub-Saharan Africa.

3. Multiple Origins

Africa is a massive continent with extreme geographical context (such as the Sahara dessert separating the North), and so it took time for iron production to spread, resulting in suggestions that there where multiple places of origin. The rich geological distribution of iron ore means they had the raw material readily available creating a high potential for multiple origins of production. Other necessary resources available to a region such as wood and water would have influenced these localities. From archaeological evidence through to production methods used in parts of Africa today there is such diversity in traditions and techniques that for it to have all began from one place and one technique can seem unlikely (Holl 2000, pg 9).

A good example of the issues that arise when trying to implement a theory is a site at the Termit Mountains, in eastern Niger. Artefacts of copper and iron where found which dated as far back as ca 1500 b.c. and furnaces dating back to ca 800 b.c. So does this suggest that the community was importing these objects before they started to produce it themselves or worked out the technology to produce it themselves? Or was it simply that the archaeological evidence for the earlier furnaces did not survive whilst the artefacts themselves did (Childs et al. 2005 pg 278)? Whilst a definite conclusion cannot be put to these situations its important to bear in mind other aspects of the problem, such as is there any evidence for mining, beneficiation, are there the local resources available such as wood, iron ore, water or would they have had to be traded in? Also iron production techniques were kept a closely guarded secret and so perhaps this influenced the time it took for them to be able to implement the technique.

Archaeological evidence

Archaeological evidence for iron production has often been based on iron artefacts found in the field. Artefacts are often in poor condition from corrosion and can be unidentifiable. Basing a context of origins to the specimens is unreliable as it is possible that the artefact may have been made somewhere completely different to where it was discovered (possibly even imported!). Solid evidence for iron production includes; the used bowl (foundation) of furnaces, tuyères and slag (from the furnace or forging process). The bloom itself and bellows are rarely found. Evidence of mining and beneficiation of iron ore can also be used as evidence; however it is possible that after beneficiation the ore travelled far to the next stage of production. Evidence for mining is often lost due to more recent mining of iron ore outcrops. Dating can be done through slag analysis and radiocarbon dating of the charcoal used to fuel the furnace. Both of these pieces of evidence are useful as they will always be produced in all smelting even if the technique varies. Metallography and petrographic analysis are also performed on specimens of slag and charcoal to help understand the conditions created within the furnace. Archaeologists have made reconstructions of the technology used for iron smelting as an important process in understanding how the ancient technology worked and to inspire confidence that their perception of the techniques used are correct.

Techniques

Iron ore is readily available over Africa. Often a diagnostic red colour, it would have made it easy to make surface finds. Common ores used were likely to be hematite, magnetite and limonite (Childs et al 2005 pg 282). The production process included mining, beneficiation, travel, smithing and forging. The mining and preparation of ores was carried out by men, women and children. It is likely that beneficiation occurred relatively near the site so the iron ore was then ready for transportation to the smelting site or alternatively ready to be traded. The original iron production technique in Africa is thought to have been the ‘bloomery process’. Bowl, shaft and natural draft furnaces have been recovered. Iron ore would be put into a furnace along with charcoal at temperatures ranging 1,100- 1,200^oC. For this process it would have been necessary for the smelters to use tuyères to blow oxygen into the furnace creating the high temperatures necessary. As the iron separated from the waste slag the raw iron product is called the bloom. The bloom is then removed, reheated and forged by a smith into shapes for use. Evidence from the shape of slag found at smelting sites suggested the furnaces were tapped.

Uses

Iron was not the only metal to be used in Africa; copper and brass were widely utilised too. However the steady spread of iron meant it must have had more favourable properties for many different uses. Its durability over copper meant that it was used to make many tools from farming pieces to weaponry. Iron was used for personal adornment in jewellery, impressive pieces of artwork and even instruments. It was used for coins and currencies of varying forms. For example kisi pennies; a traditional form of iron currency used for trading in West Africa. They are twisted iron rods ranging from <30cm to >2m in length. Suggestions for their uses vary from marital transactions, or simply that they were a convenient shape for transportation, melting down and reshaping into a desired object. There are many different forms of iron currency, often regionally differing in shape and value. Iron did not replace other materials, such as stone and wooden tools, but the quantity of production and variety of uses met were significantly high by comparison.

Social and cultural significance

It is important to recognise that whilst iron production had great influence over Africa both culturally in trade and expansion, as well as socially in beliefs and rituals, there is great regional variation. Much of the evidence for cultural significance comes from the practises still carried out today by different African cultures. Ethnographical information has been very useful in reconstructing the events surrounding iron production in the past, however the reconstructions could have become distorted through time and influence by anthropologist’s studies.

Iron smelters and smiths received different social status depending on their culture. Some were lower in society due to the aspect of manual labour and associations with witchcraft, for example in the Maasai and Tuareg (Childs et al. 2005 pg 288). In other cultures the skills are often passed down through family and would receive great social status (sometimes even considered as witchdoctors) within their community. Their powerful knowledge allowed them to produce materials on which the whole community relied. In some communities they were believed to have such strong supernatural powers that they were regarded as highly as the king or chief. For example an excavation at the royal tomb of King Rugira (Great Lakes, Eastern Africa) found two iron anvils placed at his head (Childs et al. 2005, pg 288 in Herbert 1993:ch.6), suggesting their importance and powerful significance. In some cultures mythical stories have been built around the premise of the iron smelter emphasising their god like significance.

Rituals

The smelting process was often carried out away from the rest of the community. Ironworkers became experts in rituals to encourage good production and to ward of bad spirits, including song and prayers, plus the giving of medicines and even sacrifices. The latter are usually put in the furnace itself or buried under the base of the furnace. Examples of these date back as far as the early Iron Age in Tanzania and Rwanda (Schmidt 1997 in Childs et al., 2005 pg293).

Some cultures associated sexual symbolism with iron production. Smelting is integrated with the fertility of their society, as with natural reproduction the production of the bloom is compared to the conception and birth. There are many strict taboos surrounding the process. The smelting process is carried out entirely by men and often away from the village. For women to touch any of the materials or be present could jeopardise the success of the production. With the men away from the fertile women it reduces temptation which otherwise could depreciate the productivity of the smelt. The furnaces are also often extravagantly adorned to resemble a woman, the mother of the bloom.

Cultural significance

The Iron Age of Africa was based around the agricultural revolution, driven by the use of iron tools. Tools for cultivation and farming made production far more efficient and possible on much larger scales. Fishing hooks, arrow heads and spears aided hunting. Iron weapons also influenced warfare. These items, in addition to the production of other iron goods helped stimulate economic activity, the rise of chiefdoms and even states. The control of iron production was often by ironworkers themselves, or a “central power” in larger societies such as kingdoms or states (Barros 2000, pg154). The demand for trade is believed to have resulted in some societies working only as smelters or smiths, specialising in just one of the many skills necessary to the production process. It is possible that this also led to tradesmen specialising in transporting and trading iron (Barros 2000, pg152). However not every region benefited from industrialising iron production, some suffered environmentally from problems that arose due to the massive deforestation required to provide the charcoal for fuelling furnaces (for example the ecological crisis of the Mema Region (Holl 2000, pg48)).

Bibliography

• Killick, D. 2004. Review Essay: What Do We Know About African Iron Working? Journal of African Archaeology. Vol 2 (1) pp135-152

• Schmidt, P.R., Mapunda, B.B., 1996. Ideology and the Archaeological Record in Africa: Interpreting Symbolism in Iron Smelting Technology. Journal of Anthropological Archaeology. Vol 16, pp 73-102

• Rehren, T., Charlton, M., Shadrek, C., Humphris, J., Ige, A., Veldhuijen, H.A. Decisions set in slag: the human factor in African iron smelting. La Niece, S., Hook, D., and Craddock, P., (eds). Metals and mines : studies in archaeometallurgy. 2007, pages 211-218.

• Okafor, E.E., 1993. New Evidence on Early Iron-Smelting from Southeastern Nigeria. Shaw, T., Sinclair, P., Bassey, A., Okpoko, A (eds). The Archaeology of Africa Food, Metals and Towns. London, Routledge, pp432-448

• Kense, F.J., and Okora, J.A., 1993. Changing Perspectives on Traditional Iron Production in West Africa. Shaw, T., Sinclair, P., Bassey, A., Okpoko, A (eds). The Archaeology of Africa Food, Metals and Towns. London, Routledge, pp449- 458

• Muhammed, I.M., 1993. Iron Technology in the Middle Sahel/Savanna: With Emphasis on Central Darfur. Shaw, T., Sinclair, P., Bassey, A., Okpoko, A (eds). The Archaeology of Africa Food, Metals and Towns. London, Routledge, pp459-467

• Buleli, N’S., 1993. Iron-Making Techniques in the Kivu Region of Zaire: Some of the Differences Between the South Maniema Region and North Kivu. Shaw, T., Sinclair, P., Bassey, A., Okpoko, A (eds). The Archaeology of Africa Food, Metals and Towns. London, Routledge, pp468-477

• Radimilahy, C., 1993 Ancient Iron-Working in Madagascar. Shaw, T., Sinclair, P., Bassey, A., Okpoko, A (eds). The Archaeology of Africa Food, Metals and Towns. London, Routledge, pp478-473

• Kiriama, H.O., 1993. The Iron Using Communities in Kenya. Shaw, T., Sinclair, P., Bassey, A., Okpoko, A (eds). The Archaeology of Africa Food, Metals and Towns. London, Routledge, pp484-498.

• Collet, D.P., 1993. Metaphors and Representations Associated with Precolonial Iron-Smelting in Eastern and Southern Africa. Shaw, T., Sinclair, P., Bassey, A., Okpoko, A (eds). The Archaeology of Africa Food, Metals and Towns. London, Routledge, pp499-511

See also

• Smelting
• Iron
• Iron ore
• Tuyères
• Beneficiation
• Mining
• Bloomery
• Slag
• Africa
• Bantu expansion