Monday, 20 April 2015

The Iceni hypothesis — part two

Max Planck (1858-1947)
The father of quantum mechanics
On Friday night, Robert Van Arsdell filled in some gaps in my blog entry of that day, by telling me that it was John Talbot who was working on the Iceni die-links, and that he has finished them. Thanks, Bob! So we should be good to go (providing the photographs are not 1:1 scale printed in a very low-res halftone. I much prefer the web with its "click to enlarge"). As most of my interest, for the last few years, has been in early Celtic art, I have not been keeping up with all of the latest Celtic numismatic achievements.

On the weekend, I was struggling to invent a term that would serve as the philosophical basis for my Iceni hypothesis. I settled on quantum numismatics. The term exists only in two applications: the first was in a long sentence parodying modern academic terminology (as it would seem to be an absurd term at first glance), and the second was its use as a business name (as in the not-quite literate phrase "quantum-leap" which gives an impression of being huge).  In physics, a quantum (plural: quanta) is the minimum amount of any physical entity involved in an interaction. (Wikipedia definition), so it's not huge at all. The Planck length is 1.61619926 × 10-35 meters; a distance so small you could not see it with a scanning electron microscope.

I came by my definition honestly: my "Rosetta Stone" for deciphering Coriosolite coin chronology was in noting that a small group of coins within J.-B. Colbert de Beaulieu's Class III had variations where a lash from the banner in front of the chariot pony either terminated in its tail ornamentation or connected to the driver's forehead and these were also combined with different designs for the pony's ears. That there were overlaps in these features made me realize that the traditional numismatic classification method that found importance in dominant design elements was not workable. For example, I have even seen an instance of where the coins were separated by "the boar or lyre mintmarks" (my Italics). These boar and lyre variants have the same religious iconographic original meaning (the dawn of the solar year) and the differences and later usage are all to do with specific cultural syncretisms. Their size on coins reflects their religious importance and have nothing at all to do with either coin die identity or any heraldic application. Once I understood this, I was able to rough out the entire chronology of the Coriosolite issues in just a few hours, after being baffled by it all for many months. It was a matter of evolutionary cladistics to chart it properly. God is in the detail, as the saying goes. The maximum number of dies in all of the series that had any internal subjective order was only five, and the chance of error was minute because of the many features I used (far more than like the six numbers in some lotteries).

Colin Haselgrove (BAR 222, 1992, p. 123) had noted that any single archaeological site could only tell us so much about the Celtic coins that it contained, and that in the light of finding too few data from one site, the thing to do would be to frame questions in a broader sphere through comparisons of numbers of sites with similar characteristics. He, too, came about this honestly through his Ph.D thesis which was published as Iron Age Coinage in South-East England: The Archaeological Context (BAR 174, 1987, 2 volumes).
I read this massive work three times in quick succession, hoping, unsuccessfully, that a single site would reveal something new and certain about British Celtic coins.

Haselgrove's method was intuitive and can often work in a "general trend" sort of way, but as the Iceni silver hoards are all so homogenous, we really need to look for very small variations in their makeup, and have to include other sorts of deposits that show similar clues in that particular case. We cannot treat the hoards like a series of archaeological sites and really have to go far beyond Iceni boundaries to find what we are looking for, so in a sense, Haselgrove's method is better than he might have imagined it to be when it gets expanded a bit to include even non-archaeological material.

When the metal detectorist Dean Crawford was puzzled by a Dobunni site that he had discovered and asked me about it. I had a eureka! moment. You can read about its significance in the blog post his name links to. An update to that post is the corrected XRF analysis: After Trefor contacted me about his plans to study the materials issues of the recent Jersey hoard, I gave him some of the samples that Dean had sent me so that I could get a properly done analysis and so that he could run some tests on the equipment prior to getting any of the Jersey coins. I had thought that the small silver pellets he found in some numbers at the site might well be related to some similar pellets found in an Iceni hoard I had just been reading about. I don't think that these other pellets have been analyzed. Imagine my surprise when the analysis revealed that the pellet was not even silver alone, but was the same "white gold" silver rich gold alloy as I found in a Norfolk Wolf Stater analyzed by Peter Northover, also in BAR 222. Even the non-alloying element of tin was in the same proportion. The site also contained quite a number of Thurrock potins (multiple finds on the original ground surface and not a scattered hoard). The small ingots at the same site also looked silvery and I was expecting to see that the pellets and ingots were all part of the same metalworking project that seemed to have taken place there (as evidenced by a much later cut denarius of Antoninus Pius that marked the end of the site sequence).

Trefor delivered another shock to my system by revealing that the ingots were actually a very tin-rich potin (higher Sn content than the Thurrock potins themselves). This fact also adds further confirmation to my hypothesis that the Dobunni were the manufacturers of the Thurrock coin-like ingots that are found in hoards in the South East where they could be shipped by a sea/overland route to Massalia in the south of France. Their Massalia derived design indicating not influence from, but subsequent use for the copper coinage of that city. The latter coinage is known to have the lowest tin content of all Greek bronzes, and although most analyses of that coinage has not looked for the cobalt and nickel impurities in Massaliote bronze, one conducted by Ulrich Zwicker did, indeed find it (Northover op. cit.) This ratio identifies the source as British bronze, and not the typical continental bronze. There would have been no reason at all for the Massalians to have the need to import bronze from Britain, but they had experienced great problems from Carthaginian pirates seizing ships bringing British tin to their port and must have realized that an overland route would be far safer. The first tin shipments from the Dobunni would have been via the Durotriges at Hengistbury, probably to the Coriosolite port and thence, via the Redones, either overland to Massalia, or partially through a Veneti sea route landing northwest of Massalia and avoiding the Mediterranean. We must also ask ourselves just how early these Thurrock potins might be as Carthage was destroyed by the Romans in 146 BC. and the Massilote bronze coinage started in about 200 BC. Mark Fox (who quotes me -- slight spoiler alert!) has some fascinating things to say in this article on the Thurrock potins.

Dobunni profit was possible because the tin was debased with copper and after Cassivellaunos made his little deal with Julius Caesar to cut out the Durotriges trade and bring Roman imports to the areas that he controlled, the subsequent tin trade went through the south east. Caesar must have thought the real motive was to obtain Roman trade, alone, but all trade is two-way anyway. The profit vanishes with empty ships unless you are some sort of raider or pirate. There must have been a long tradition of trying to cut out the Durotriges trade before Caesar. The later potin coins produced in the southeast contained even less tin. It was quite the little economy going on. Although it lacks recently discovered information, this paper, by Haselgrove has some interesting stuff about the Co, Ni profile etc. with regard to potin coins and Massalia.

Now, if you think all of this is strange and byzantine, you are in for an even greater shock tomorrow. It's fun playing Scheherazade!

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