Time to exchange a few war ponies for shipping amphorae |
Trade disputes could also lead to warfare and those who had benefited from long trading partnerships were obviously not going to willingly share these relationships with anyone else. Short of warfare, the best way to increase trading profits was through making enough new allegiances and gaining enough support to transform any trade from local to tribal, or even confederation importance. Without such support, too many middle men would have divided the trade to a point where it would be inflationary and no one could benefit that much. At the bottom end of such trade, certain non-perishable commodities would have been stored waiting for the prices to recover. This could explain the numbers of later British potin coins from hoards close to the shipping ports around the Thames estuary.
Because of long term trading agreements over tin, and the competition for such trade between various cultures, tin was being traded that had already been alloyed with a certain amount of copper. Each time the tin traded hands, a little mere copper could be added to increase the profits, but if the alloy got too debased it could be noticed by those who had some experience in the matter. Inevitably, some traders would get a bad reputation if they tried making too much and then they would sell nothing.
I started to think about seigniorage when I noticed that pellets and small ingots from a south Worcestershire site contained more tin than their alloy type would suggest. It made sense that tin would dominate local alloys because the Dobunni was close to its source. The ingot was especially telling because it was while gold, and the Dobunni used gold more heavily alloyed with copper than with silver. The Durotriges also had some silver alloy coins with alloying amounts of tin in them, but those alloys had greater amounts of copper, too. The only coin alloy I could find that was very close, was a white gold Norfolk wolf stater, but there were no analyses showing much tin in these. The later Iceni gold staters of the Freckenham type also had tin as an alloying metal sometimes, but like the Durotriges, the copper content of these coins was too high. There is also a possibility that some Snettisham torcs have a closer alloy to the Dobunni site ingots, but I have yet to be able to check this.
So where did the Worcestershire white gold ingots originate? You would think that it would be Iceni territory as that is where we find the closest white gold alloys. No Dobunni gold coins contains tin in anything more than trace amounts. Yet any tin of alloying quantities must have passed through the hands of the Dobunni at some point. Only the small amount of tin in a gold coin appears because recycled bronze was used as the copper in the alloy. The Dobunni now provide a reason for adding tin and copper to silver and gold for gold stater alloys. Before this, it was naturally assumed that a small amount of tin in a gold coin meant that recycled bronze was being used in the alloy.
As the South Worcestershire site dates after 50 BC, none of the high tin bronze there has the high cobalt to low nickel ratio of native British (west-country) copper, the copper seems to be a continental import. It is still not clear, though, if the copper was added to the tin close to the mine site, or was the "export grade" tin of the Dobunni; were the pellets the alloy that the Dobunni bought or the alloy they sold?
We can complicate matters even further by saying that even if the white gold ingots were Dobunni products, they could have been returned as a tribute by the Iceni, themselves. We do not get that problem with the Iceni hypothesis because it notes die links within a narrow range of the coin chronology at discrete deposits that were not subsequently spread any further (unlike the big silver coins hoards). Seigniorage factors are a good way of plotting primary distribution, but does no good for detecting any recycling or reuse. It only becomes most likely that the offering of the white gold ingots represented someone in Dobunni territory who was supplying such an alloy for the Iceni, and not a certainty.
More tomorrow...
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