A Cultural Climate Measure from Iron Age Africa

South of the Zambezi River, along the eastern side of Africa, things get dryer and dryer as you go south, until you finally reach the southernmost end of the continent where things become a little bit moister again.

A couple of thousand years ago cattle keeping people speaking Bantu languages and possessing mainly Banutu cultural traits ... the ancestors of the present day Shona, Venda Tswana, Zulu, etc. .... were living in this area, keeping their cattle, and doing all sorts of interesting stuff.

As climate fluctuated year to year and decade to decade, there moved north and south a kind of line ... an uneven line following topography and affected by numerous other forces, a line as hard to define or keep track of as the shadow of a train running down the track, cast on the nearby forest ... that determined where, if you were a Bantu cattle keeping group, you could live vs. not live. This was essentially the line that divided areas wet enough for enough of the year to reliably grow sufficient grass for the cattle to graze (to the north, more or less) vs. areas where the rainfall was insufficient, or insufficiently regular, for this to happen (to the south, more or less).

It stands to reason that cultures that lived near this line would experience significant fluctuations in all sorts of areas of life. Cattle meant food, but cattle also meant wealth. This line could be though of as a sort of depression/recession vs. good economy line. Imagine such a line wafting back and forth across Europe. One day you are on the correct side of the line and everything is fine, then a couple of years later the line moves and the country you live in is destine to experience two or three decades in which the money is always worth a tenth of what it otherwise might be worth.

So what's a culture to do? Invent religion, of course! Or, more realistically, adapt the religious modality to at least attempt to address variability in rainfall.

Well, the modern cultures of the region have ritual practices that many believe can be seen in the archaeological record, and some of those practices involve rain (or the lack thereof). And this has led to a very interesting research outcome about to be published in the Journal of Archaeological Science.

Tom Huffman, with whom I have had the good fortune to spend a bit of time with in his field area in Botswana, has developed a "cultural proxy for drought." This is the identification of certain rituals that indicated increased drought in the southern African Iron Age.

This is the area of interest:

Note that the norther part of this area is the location of the famous Great Zimbabwe. Near the center of the map is the Limpopo/Sasha river system. Traditionally, this has been considered a sort of "do not cross" line by archaeologists, with certain Iron Age cultures seeming to stall out on their southerly migration. Research by Huffman and many others has shown that the real story is much more complex than this, with various groups moving across the landscape in a much more complex way.

From the paper's abstract:

In traditional Bantu-speaking societies in southern Africa, drought is caused by breaches in rules of pollution. At times of severe drought (3-5 consecutive seasons), rainmakers ascend special hills to perform special rituals. The archaeological signature of this unique activity forms a cultural proxy for drought. New research shows that burnt daga structures also correlate with high Delta-15N values for small stock. Burnt structures thus form a new component to the proxy. According to the ethnography, farmers implicated in the cause burnt their grain bins, and sometimes houses, as a ritual of cleansing. The dating of these structures provides a revised climatic sequence for the plateau portion of the summer rainfall region. Among other new results, there was a drought at the end of the Mapungubwe period (ca. AD 1300). At about AD 1650, droughts associated with the arrival of maize caused people to stop growing it as food for a while.

It is like having your own ethnographic weathermen reporting to you from beyond the grave....

Have a look at the burned layers in this photograph:

This is where a house at Mapungubwe (one of the key sites in the ara) was cleansed twice.

... on the summit, rehabilitation work ... exposed a double house; that is, one house AC floor had been burnt and another built directly on top of it .... This double house floor dates to the Transitional Period and is therefore contemporaneous with the double grain bins in commoner homesteads. Evidently, cleansing rituals applied to every one.

Another interesting aspect of the double-burnt houses is this: Ethnohistorically, if a person is convicted of being a witch, their house would be burned down, which would result in a sort of false positive for a dry season. However, a witch's house cannot be rebuilt. So the double-burnt houses, which are certainly rebuilt, are not witch's homes. (Of course, I might expect more such accusations and convictions to occur during times of drought...)

T HUFFMAN (2008). A cultural proxy for drought: ritual burning in the iron age of southern africa Journal of Archaeological Science DOI: 10.1016/j.jas.2008.11.026