I have now gone on at great length about the polyptych of Santa Giulia di Brescia without really talking about my actual purpose in reading it, so it’s time to do that.1 You may remember a long time back that I had a go at the idea, repeated in textbook after textbook, that agriculture in the Carolingian period ran at yields hardly more than the grain that was sown.2 This is self-evidently ridiculous if you are familiar either with actual growing of crops (which I am only second-hand) or can do basic maths, but it persists, and the reason it persists, like many another medieval cliché, is Georges Duby.3
This is not entirely Duby’s fault. He wrote a couple of textbooks in the 1960s and 1970s that somehow remain the world standard for any history of the early medieval economy that actually contains agriculture, and he used the best thinking available and sources known at the time.4 He did a pretty good job of synthesis on that, and though one might wish he’d thought about it a bit harder, it’s really not just him who’s failed to do so, and those that have thought about it haven’t really looked hard enough at his evidence.5 That was, in large part, the Carolingian estate survey of the fiscal centre at Annapes preserved in the text known as the Brevium Exempla, and some time ago already now I gave a paper at Kalamazoo in which I showed that Duby had in fact read the text wrong, or rather failed to read all of its data, as had all those he used, even, I’m sorry to say, Philip Grierson, and I considered that dispatched and proceeded to writing it up.6 But Annapes was not Duby’s only source that seemed to support these awfully low yields, and so I needed to see if the same tricks could be performed with the others too, and you will by now have guessed or maybe already know that one of them was the polyptych of Santa Giulia di Brescia.
Duby dealt with the figures from Santa Giulia only in summary fashion. In Rural Economy and Country Life he works Annapes over extensively, coming up with output figures of between 1·5:1 and 2·2:1, and then goes on:
“We must not, of course, generalize from one set of figures obtained from a single source. But it is possible to find elsewhere some other traces of output, somewhat higher than that which can be derived from the Annapes inventory, but even so representing a low yield and a derisory rate of profit when compared with the value of the capital in land and seed corn. One significant fact is that compilers who visited the farms (cours [apparently left in French from Latin ‘curtes’]) of the abbey of San Giulia of Brescia in 905-906 to compile a polyptych found there reserves of grain in the barns which were barely higher and sometimes lower than the quantity needed for sowing. Thus at Prozano where the fields could take 300 muids of seed corn, the stocks in the estate barn amounted to only 360 muids of which 140 were of millet (mil). At Canella 90 muids were needed for sowing and 51 were in the barns; at Temulina 32 and 37.”
And with that he moved onto Saint-Germain-des-Prés near Paris and pulled a similar trick there.7 And in the slightly later and much shorter Early Growth of the European Economy he didn’t even give that much detail (or a reference to the primary source), limiting himself to dealing again with Annapes and then adding:
“The Lombard monastery of St Giulia of Bréscia [sic], which consumed some 6,600 measures of grain annually, would have 9,000 sown to cover its needs, which means that the return normally available to the lord was being estimated at 1·7 to 1.”8
The best way to see what is wrong with this is to look closely at how the compilers of Santa Giulia’s polyptych were using their figures, figures that I’ve already argued here they were receiving in a standard format. And doing so shows firstly that Duby, and Luzzatto before him, were again wrong in assuming that these figures mean what they wanted to mean, and in fact that using them to calculate yield is impossible except in one single case where the formula was bent, and in that case it comes out at at least 4·25:1 and probably rather higher. Don’t believe me? Watch this!
“In the curtis of Mairano, 2 houses, 3 caminatas, arable land for the sowing of 150 modia, vine for 35 amphorae, meadows for 20 cartloads, wood for fattening 100 pigs; 1 mill, whence 12 modia of grain come per year; 9 prebendarii within the curtis, male and female together; 5 modia of corn, 52 modia of rye, 6 modia of oats, 1 modium of legumes, 70 modia of millet; that is, 133 modia; 24 amphorae of wine, 3 oxen, 35 pigs, 12 sheep, 4 goats, 7 geese, 20 chickens; cheese, 12 pounds of wool; and there are seven lots, on which reside 11 slaves, each one of them does 4 days work in the week; and there are 11 other lots, on which reside 11 free men; eight of them do three days work in the week, and 3 of them do 2 days work in the week and render 15 denarii in silver; and there are 3 lots, on which reside 3 tenants, who render the third modium of grain, half the wine and 5 ploughshares; 1 vacant lot, whence come 6 modia of grain and 2 amphorae of wine a year.”9
This is a pretty typical estate, except for the render in ploughshares. And immediately you can see where Duby’s figures were coming from: the estate had land you could sow 150 modia on and they only had 133. Case closed? You might think so, except…
For this to work as Duby assumed, three things need to be true. Firstly, the allotments need not to be in the main count of arable. Since the slaves and freemen were apparently keeping what they grew, the tenants were keeping two-thirds of it and we don’t know either how much land any of them had or what they managed to grow from it, including them makes the figures basically unusable straight away. I think this assumption is probably correct, though, because there are several cases where the tenants are rendering far more wine than the estate’s count could apparently deliver, some where they render chestnuts or olives and the estate’s count includes no such woods, and so on, so it seems likely that the allotments were uncounted. So Duby was right? Well, except…
The second thing that has to be true for Duby’s maths to work is that the grain counted needs to be the whole harvest, less the crop sown for next year. That’s problematic, because we don’t actually know what time of the year these figures were taken. One would like to guess based on whether it was spring or winter crops they had more of in the barns, but since we don’t know which was sown when here that gets us nowhere. We also don’t know – and this is what also gets him at Annapes – how much of the harvest might already have been distributed, because unless the figures were everywhere taken in the immediate aftermath of the harvest, there were two obvious drains on the crop, the first being the paid workers, the prebendarii, whom this crop had to feed, and the second of course being the monastery to whose ultimate benefit this estate was being run. Of course, if you were as estate managers actually interested in what your fields were yielding, you would need to count the crop as it came off, but that isn’t what these people were counting: as at Annapes, they were presumably counting what remained to be eaten or sold once the regular amounts had been taken out. So unless we can measure that somehow, we can’t hope to get yields out of these data. I’ll come back to this, but it’s enough to wreck the whole enterprise. Surely there can be nothing else wrong? Well: except…
The other thing that needs to be true for Duby’s maths to work is that the arable land counted needs to actually all have been in use for growing. If, for some reason, the estate was not running at full capacity and they were only sowing, say, 100 modia, then suddenly the yields that we in any case can’t calculate from these figures look better by a factor of a third. Have we any reason to suppose this, you ask, and I say, yes, in fact we have two. Firstly, observe the wine. Here it seems as if the same logic should apply as for the grain: the vines could produce 33 amphorae and they had 24. But the first figure here is not planting seed, as with the grain: you can take a vine’s whole crop and it will produce at the same rate again next year, you don’t have to stick grapes back in the ground to ensure next year’s vendage. If these vineyards were inventoried that year as being able to produce 33 amphorae despite there being only 24 amphorae to show this, it just makes no sense to suppose that they were somehow underperforming. This makes one of two things ineluctable: either the estate was not in fact growing everything it could produce (which the number of pigs also suggests, unless this was after the winter slaughter, in which case it was also long after the harvest and even longer after the vendage), or else some of what it did had already been shipped our or consumed. And if you accept this with the wine, as you kind of have to, then it can obviously also be true of the grain. So, OK, in that case, you might say, we actually have some kind of figure for consumption. One could multiply the yield figures by that factor of 33/24 to allow for that and it might even mitigate some of the reservations above, no? Well . Except…
Except that for heaven’s sake the whole arable can’t have been in use at once in any given year, not unless they wanted to make it useless in short order; somewhere between a half and a third of it must have been lying fallow. I don’t see anything intrinsic to this text that allows us to say whether Santa Giulia was running its estates on two-field or three-field rotation, but the state of the literature seems to think that it should be three-field by now, in an ex-Carolingian grand domain, let’s assume the latter: that still means that only 100 modii would have been sown that year at Mairano.10 So: in order to have a ghost of a chance of being right Duby’s figures should actually be: 100 modia sown, (133 x 33/24) back, for a yield of 1·82:1, and that’s already assuming a lot (such as that the next year’s crop had not already been sown, in which case it would be 2·82:1 minimum) and probably missing a range of other factors that make the exercise silly to attempt anyway. Can we do any better?
Well, actually, maybe. There is one entry in the polyptych that clarifies things a little bit more. At Canelle Secco, where you could put 90 modii in the ground and they had only 51, they also had 16 prebendarii and 39 tenants of the various classes we’ve already described, and here, almost uniquely, the compilers tell us: “and the above-named prebendarii and tenants take (tollent) 195 modia of grain a year”.11 (I guess that the tenants got grain by way of food when they were labouring on the reserve as most of them were obliged to do.) This means that without even worrying about what was still in the barns, we actually have here something like operating figures, and these imply that in a working year, of their 90 available modium-containing units they’d sow probably 60 and get back at least 60 + 195 = 255 modia. This, bear in mind, assumes that the monastery got nothing at all from its investment. The tenants’ renders suggest that in fact we should be considering it getting at least a third of the grain and probably rather more, but let’s not worry about that just yet, because it means introducing made-up figures again. Even if the monastery had taken nothing of what was produced at Canelle Secco in an ordinary year, the estate’s yield must have been at least 255/60:1, which is 4·25:1. That is the minimum at which this system could have been maintained, but we should actually expect it to be more; if I had to guess I’d say probably give the monastery basically as much as the workers and make it more like 7·5:1 but that’s already made-up, and we know what happens to made-up figures.12 So not only do we, here as elsewhere, have all kinds of reasons to suppose that results of 2:1 yields extracted from this source are basically founded on a range of unjustifiable assumptions that make those figures no better than prejudice: actually, the source itself contains material for figures that show that such results are ridiculous. If anyone tries to tell you that Santa Giulia’s estates ran at yields of any less than 4·25:1, this makes them wrong, and nearly twice as much is probably a justifiable guess. And thus I refute Duby. I thank you.
1. Gianfranco Pasquali (ed.), “S. Giulia di Brescia” in Andrea Castagnetti, Michele Luzzati, Pasquali & Augusto Vasina (edd.), Inventari altomedievali di terre, coloni e redditi, Fonti per la Storia d’Italia 104 (Roma 1979), pp. 41-94, also printed in Ezio Barbieri, Irene Rapisarda & Gianmarco Cossandi (edd.), Le carte del monastero di S. Giulia di Brescia (Pavia 2008), I no. 46 whence online here.
2. E. g. Robert Fossier, L’Enfance de l’Europe : X-XIIe siècles (Paris 1982), p. 615; Norman Pounds, An Economic History of Medieval Europe, 2nd edn. (London 1994), p. 198; Adriaan Verhulst, The Carolingian Economy (Cambridge 2002), pp. 32-33; Jo Ann Hoeppner Moran Cruz & Richard Gerberding, Medieval Worlds: an introduction to European history, 300-1492 (Boston 2004), pp. 162 & 223.
3. For figures from these eras, see P. F. Brandon, “Cereal Yields on the Sussex Estates of Battle Abbey during the later Middle Ages” in Economic History Review 2nd Series Vol. 25 (London 1972), pp. 403-420, DOI: 10.1111/j.1468-0289.1972.tb02184.x, although there is now vastly more high medieval data available as Bruce M. S. Campbell, Three centuries of English crop yields, 1211-1491, ed. David Hardy, online here. There is also very sound discussion in Peter Reynolds, “Mediaeval cereal yields in Catalonia & England: an empirical challenge” in Acta Historica et archaeological mediaevalia Vol. 18 (Barcelona 1997), pp. 495-507, online here, repr. in Immaculada Ollich, Montserrat Rocafiguera and Maria Ocaña (edd.), Experimentació Arqueològica sobre Conreus Medievals a l’Esquerda, 1991-1994, Monografies d’Arqueològia Medieval i Postmedieval 3 (Barcelona 1998), mostly online via Google Books here, pp. 121-128.
4. G. Duby, L’Économie rurale et la vie des campagnes dans l’Occident médiéval (Paris 1962), transl. Cynthia Postan as Rural Economy and Country Life in the Medieval West (London 1968, repr. Philadelphia 1998) and G. Duby, Guerriers et paysans, VIIIe-XIIe siècles. Premier essor de l’économie européenne (Paris 1973), transl. Howard B. Clarke as The Early Growth of the European Economy: warriors and peasants from the seventh to the twelfth century (London 1974). Such matters are not covered in Michael McCormick, The Origins of the European Economy: communications and commerce AD 300-900 (Cambridge 2001); more surprisingly, there’s also no discussion of productivity except as affected by aristocratic pressure in Chris Wickham, Framing the Early Middle Ages: Europe and the Mediterranean, 400-800 (Oxford 2005), pp. 535-550.
5. There is a round-up of discussion in J.-P. Devroey, Économie rurale et société dans l’Europe franque (VIe-IXe siècles). Tome I : fondements matériels, échanges et lien social (Paris 2003), pp. 115-117.
6. The most accessible edition of the Brevium Exempla is still A. Boretius (ed.), Capitularia regum Francorum I, MGH Legum Sectio II: capitularia regum francorum I (Hanover 1883, repr. 1984), online here, no. 128, pp. 250-256; see now Darryl Campbell, “The Capitulare de Villis, the Brevium exempla, and the Carolingian court at Aachen” in Early Medieval Europe Vol. 18 (Oxford 2010), pp. 243-264, DOI: 10.1111/j.1471-28847.2010.00298.x. Also mentioned here: P. Grierson, “The Identity of the Unnamed Fiscs in the Brevium exempla ad describendas res ecclesiasticas et fiscales” in Revue belge de philologie et d’histoire Vol. 18 (Bruxelles 1939), pp. 437-461, DOI: 10.3406/rbph.1939.1300; J. Jarrett, “2:1 against: cereal yields in Carolingian Europe and the Brevium Exempla”, paper presented in session ‘The Court and the Courts in the Carolingian World’, 46th International Congress on Medieval Studies, University of West Michigan, Kalamazoo, 15th May 2011.
7. Duby, Rural Economy, pp. 25-27, quote on p. 26.
8. Duby, Early Growth, p. 28.
9. G. Pasquali, “S. Giulia di Brescia”, p. 69. In what follows, where no reference is given it’s in the polyptych, and you can either find it in the online version here or wait for the publication…
10. Devroey, Économie rurale, pp. 108-111; N. B. that Duby, Rural Economy, pp. 22-25, could argue for the necessity of huge fallow areas without in any way factoring them into his calculations of yield beginning on the same page (see n. 7 above) and yet no-one has ever pulled him up on this as far as I can see because apparently medieval historians just can’t understand numbers!
11. Pasquali, “S. Giulia di Brescia”, pp. 55-56.
12. They get picked up as if they were real and passed on through the literature, because as said, historians don’t understand numbers. See Theodore V. Buttrey, “Calculating Ancient Coin Production: facts and fantasies”, The President’s Address in Numismatic Chronicle Vol. 153 (London 1993), pp. 335-351 at pp. 349-351 for an eloquent plea for historians to refuse to put junk numbers into circulation.