Seminary XVII: tolls and trade and bad mathematics

Going back through old entries to find stuff, I realise that somehow I missed Seminary X. No idea how, but it’s a bit late now. In case I’ve been causing confusion, by the way, the idea was to coin an adjective that would mean `of or pertaining to a seminar’, and I thought the ambiguity would be fun. But so far it doesn’t seem to be bringing me any misdirected search hits, whereas « medieval sex » is still bringing people here with unfortunate frequency.1 But, shockingly, this isn’t what I was aiming to write about.

As well as missing virtual seminars, I have also been missing real ones I’m afraid, through a variety of causes involving some any or all of disinterest in penitentials, acute pressures of writing, clocks whose hands I set forward whilst fumbling to switch off the alarm, and general wastrel languor. But, to make up for it, the Department has been bringing seminars to me, in the form of a sudden and shortlived revival of our departmental seminar series. This was orchestrated by the tireless efforts of Rory Naismith, who arranged that on the 1st of February Neil Middleton, fresh from his appearance in Early Medieval Europe,2 could come to speak to the Department and various visitors about “Early Medieval Tolls and the Coinages of North-West Europe”.

A silver penny of King Offa of Mercia, c. 793

Mr Middleton’s basic thesis, and one that he’d very much brought for our scrutiny as numismatists, was that when early medieval monarchs changed tax levels by altering the amount that was taken at ports and other toll stations on goods that were being transported or sold, they did not do so simply by changing the amount that they charged, because the proportion that was permitted in each place often seems to have been ancient, traditional and invariant over many centuries. Proving that, by means of very lengthy excursuses on equivalencies of weights, was where most of the paper’s time went, but the interesting bit was the alternative, that instead, when times were bad and kings like Charlemagne or Alfred urgently needed to drum up more revenue, they did so by tinkering with weight standards. They made bigger coins, or more subtly, changed the basis of the weight to which the coins were made to a heavier one, so that for the same number of pennies or deniers levied more actual bullion came their way. It sounds vastly complicated, but really it’s easier, because you can control the coinage because you make it, or have it made, in a few places well controlled, but you may well not be able to alter market regulations across the empire or collect new tolls in places where your writ doesn’t really run. And indeed, Mr Middleton admitted to examples of places where old weight standards and coin seem to remain in circulation, and I was fine with that because Catalonia is one of them, though he didn’t know that necessarily.3

The problem is the maths. I don’t believe in the mathematics of medieval metrology. There is is no good basis for working out a weight standard except when a vast amount of evidence all points in broadly the same direction. Then, maybe, you can say that these things were made to the same standard, but it’s still only a guess. Coins come to us worn; we never know how much weight they’ve lost. Even fine ones are not going to be their mint weight, and while ancient Greek coins are usually within 0.5 g of a mean weight, medieval ones do not match up so well. And these things, because they had to contain a certain accepted amount of precious metal, are one of our best sources for medieval weight standards. Cereal grains are usually reckoned as the actual medieval basis of weight standards, and long theories have been constructed around whether this kingdom or that is reckoning weights starting from a wheat-grain or a barleycorn. Mr Middleton’s handout helpfully suggests that an average equivalence for wheat to barley is 4:3, and his figures go to three decimal places. Well, just try it. You won’t find a match to three decimal places, I know that much. He explained disparities as being down to improved breeds of the crops. Well, whatever, they just don’t grow to the same weight, sorry. And then, starting with these three-decimal place figures, he multiplies up to get a pound, which involves multiplying whatever error is involved in the base weight by a factor of 5,000. And then—surprise—it doesn’t quite make what we believe to be a Roman pound, so he rounds up, because those medievals, their weighing was a bit vague anyway, right? Only they made the evidence that he’s using, and he’s using it to prove that they were a bit slapdash because it doesn’t add up to this standard that he is arguing, from the way he’s managed to add things up so that they nearly match, they were using, based on evidence he is arguing is flawed! And furthermore he then used slight differences to argue (and he’s not the first here by a long way) for a notional pound of account that differed from the actual pound weight. And he posited a “heaping-up allowance”, i. e. the difference between a level measure and a heaped one, and shockingly, the figure he posited matched the difference he’d posited between the account and weight pounds, which obviously proves that they were using them as he said. Well, er, no. It proves he’s made up figures that fit his own sums. If there had been cake, which unusually for our seminars there wasn’t, he would clearly have been both having and eating it. There can be no foundation for conclusions based on this kind of maths.

The which is really bothersome, because what he was basically arguing makes a very great deal of sense and is a big contribution to our grasp on how kings like Charlemagne or Alfred would have tried to alter the workings of their states’ economies, and I’d really like to be able to believe that it was acceptable, and that the fine details and the dodgy maths involved beneath them don’t affect it. And they may not, but we were so drowned in worthless figures that their actual connection to the argument is hard to work out and surgically remove. So I will wind up citing this stuff, possibly, because I believe it very plausible that things could have worked this way, but I still don’t think that any of this stuff goes any distance towards proving it.

1. On the other hand, the fact that some people are getting my rant about gender theory’s divorce from the real physical passions when they were after porn amuses me, especially since they apparently still decide to click that link in the search engine despite a non-pornographic preview clip. Why? Ah well. The best ones are indubitably the misspelt ones. Chief in this regard, and unlikely ever to be surpassed, is the unfortunate person who was brought to this humble weblog searching for « historic annal sex ». Yeah, you didn’t get what you were after did you. Never mind hey? Now you know a new word for a chronicle with year-by-year records! I’m here to help!

2. N. Middleton, “Early medieval port customs, tolls and controls on foreign trade” in Early Medieval Europe Vol. 13 (Oxford 2005), pp. 313-358.

3. Mints in Catalonia made Frankish deniers like everywhere else in West Francia until 864, when King Charles the Bald reformed his coinage in the Edict of Pîtres. The Catalan stuff however continued exactly the same after the reform as before, even though the local counts were still occasionally coming to court. It’s not a deal-breaker. I expect that, being that far away, Charles was happy to have people there using money with his name on still. In 877 he gave an embassy from Barcelona ten pounds of silver to fix Barcelona cathedral roof with; they turned up, led by a Barcelona Jew called Judas, no less, just as a rebellion was breaking out and it must really have helped him to have strange ambassadors from far-off lands turning up at court and calling him king. On the coinage you can see A. M. Balaguer, Historia de la moneda en les comtats catalans (Barcelona 1999), pp. 64-67, though you’ll probably have to come here to get hold of a copy; on the counts and their loyalty, I recommend Roger Collins’s article “Charles the Bald and Wifred the Hairy” in M. T. Gibson & J. L. Nelson (edd.), Charles the Bald: court and kingdom. Papers based on a Colloquium held in London in April 1979, British Archaeological Reports (International Series) Vol. 101 (Oxford 1981), pp. 169-188, repr. in Gibson & Nelson (edd.), Charles the Bald: court and kingdom (Aldershot 1990), pp. 170-189; and the 877 embassy is known from a capitulary which is best edited as R. d’Abadal i de Vinyals (ed.), Catalunya Carolíngia II: els diplomes carolingis a Catalunya, Institut d’Estudis Catalans: Memòries de la Secció Històrico-arqueològica 2-3 (Barcelona 1926-1952), pt. II, ap. VII. So there.

3 responses to “Seminary XVII: tolls and trade and bad mathematics

  1. Pingback: Seminars LXXXVI-LXXXIX: four for the price of one « A Corner of Tenth-Century Europe

  2. Pingback: Seminar CIX: where’s the money in early Anglo-Saxon England? | A Corner of Tenth-Century Europe

  3. Pingback: I should have read this the moment I bought it, III | A Corner of Tenth-Century Europe

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