Tales of Soft Money — The Sahelian Kingdoms
Update 2020-02-18: This article is updated with further sources to better reflect its chapter in my book, Money Dethroned. It discusses a phenomenon Ibn Battúta observed while still traveling in Mali - in fact, the end-phase of the very dynamics that slowly took the world from primitive monies, to silver- and gold coinage. His observations intertwine with some interesting archeological findings on money in the area, described and summarized by Laurence Garenne-Marot on behalf of the British Museum.
Useless Metals in Kumbi Saleh
Garenne-Marot uses both translated writings as well as other evidence to piece together the monetary systems of the Sahelian kingdoms, meaning the pre-medieval Ghana Empire and its geographical successor that Battúta traversed - the Mali Empire. His short essay starts off by quoting Battúta:
The houses at Tagaddá are built of red stone, and its water run by the copper mines, so that both its colour and taste are affected. There are no grain crops there except a little wheat, which is consumed by merchants and strangers. The inhabitants of Tagaddá have no occupation except trade. They travel to Egypt every year, and import quantities of all the fine fabrics to be had there and of other Egyptian wares. (Battúta, 1325-1354, p. 335)
Later, Battúta added:
The copper mine is in the outskirts of Tagaddá. They dig the ore out of the ground, bring it to the town, and cast it in their houses. This work is done by their male and female slaves. When they obtain the red copper, they make it into bars a span and a half in length, some thin and others thick. The thick bars are sold at the rate of four hundred for a mithqal of gold, and the thin at the rate six or seven hundred to the mithqal. They serve also as a medium of exchange; with the thin bars they buy meat and firewood, with the thick, slaves, male and female, millet, butter and wheat. The copper is exported from Tagaddá to the town of Kúbar, in the regions of the heathens, to Zagháy, and to the country of Barnú, which is forty days' journey from Tagaddá. (Battúta, 1325-1354, p. 336)
In other words, it appears that he had stumbled upon a copper based monetary system, with standardization efforts in terms of divisibility and weight (mithqal) of the minted copper bars, or rods.
Some interesting archaeological findings, referenced by Garenne-Marot, and corroborating the use of copper money, were provided by Frenchmen R. Mauny and P. Thomassey, in 1949-1951. They dug up standardized copper bars in the old Muslim merchant quarter of Kumbi Saleh - a town that was previously the capital of the vanished Ghana Empire and that had conducted a lucrative trans-Saharan trade with the Berbers and Arabs in the north. These copper bars likely functioned as money, and were much older than those observed by Battúta in Tagaddá further east. One essential observation of the archaeological findings was that some of the copper bars had been diluted with lead, which meant they likely lost much of their workable use as consumable items. The implication is that as money, it didn't matter much that the metal could not be re-smelted and consumed for non-monetary purposes.
Relentless Waves of Copper
Far northwest of Kumbi Saleh lay the town of Tegdaoust - another end point of one of the many north-south trans-Saharan trade routes. New excavations during the 1960's and 70's gave a pretty clear view that copper money production occurred in the town's workshops at a time prior to Battúta's Mali expedition. Garenne-Marot argues that not only did these workshops smelt local copper ore to trade the metal with gold in the more copper-sparse parts outside the kingdom; the merchants and metal workers of the city were smart enough to likely import relatively cheap copper and brass from north of Sahara. Some evidence of this could be seen in the finding of a large number of copper bars buried in a sand dune in the Majâbat al-Koubrâ, the most arid part of Mauritanian Sahara. That excavation point was on a trade route to Tegdaoust, and as the bars consisted not of unalloyed copper, but of brass (copper with high zinc content), it became clear that they were produced outside of Ghana/Mali (probably, according to Garenne-Marot, the mines of the Sus and Daï valleys in present day Morocco). What likely happened was that these long brass bars were used in Tegdaoust workshops to dilute the locally produced and more expensive copper, without drastically altering the color of the metal. From coming in long shapes, formed to fit being carried by camels over a long distance, they were melted, blended and formed in smaller shapes to fit donkeys that carried them south to the gold-rich areas of modern-day Guinea. Even Battúta mentioned the "heathen gold" in passing:
Sultan Mansá Sulaymán was visited by a party of these [black] cannibals, including one of their amírs. They have a custom of wearing in their ears large pendants, each pendant having an opening of half a span. They wrap themselves in silk mantles, and in their country is a gold mine. (Battúta, 1325-1354, p. 332)
Garenne-Marot later speculates that, following disastrous raids on Tegdaoust, the north-south supply lines as well as copper money production shifted east towards Kumbi Saleh - something which might explain the relatively large number of small copper bars in that town stemming from a period after the raids.
The way some of the monetary flows in the area worked is now becoming clearer. Although gold was relatively prevalent all over Muslim West Africa, as well as in the North African sultanates, it was still of course highly valuable due to functioning as money. Mansa Musa's boastful account of incredible copper-to-gold exchange ratios in certain non-Muslim areas (corroborated by his almost proverbial wealth), combined with the copper- and brass production in the Empires of Ghana, Mali and in North Africa, made for an obvious result: Muslim merchants bought copper locally as well as imported copper and brass in order to export it to the gold producing tribes. As copper ore in a large enough geographical area is far easier to acquire than gold ore, this ultimately made it relatively simple to supply the south with the large amount of copper it so highly desired, and take locally abundant gold in exchange. Consequently, the gold-rich tribes were flooded with the (often diluted) corrosion prone metal, which in the end might have hurt its saleableness to a degree where gold slowly became ever more appreciated. That would have been an example of Thier's Law in action: bad copper money was ultimately driven out in favor of good gold money due to incessant monetary inflation.
Garenne-Marot argues in his essay that the considerable geographical differences with regards to copper-to-gold exchange ratios may also have had a cultural basis. In that case, it may be provided as an example where money as a social or cultural phenomenon can be wiped out anyway in the face of economic reality, meaning a relative abundance. And so, we can also with this article argue that Mengerian dynamics of money are very real, and had important repercussions on many societies and nations. One might even claim that these monetary dynamics strongly shaped history. Relative scarcities and abundances combined with ever larger trade networks and differences in technological advancement caused hundreds of monies to become mainly two: gold and silver - not by collective choice or convention, but by the actions of individuals trying to escape saleableness-related costs, including monetary inflation.