Several problems are raised by the economic/political paradigm. As indicated last time, my aim here is not to replace them but to add a new level more concerned with ideas, attitudes or culture. To this end it’s important to note that the broad outlines of economic development sketched in Part 3 match, in general, those of the shifts in culture mapped out in Part 2, of the gradual turning away from each other of west and east (especially of east).
One difficulty is the lack of fit between the political change and the archaeologically-revealed patterns of exchange. The alleged end of the western ‘tax spine’, after the Vandal conquest of Africa, does not seem to me to fit the data very well. One issue is what exactly the Vandal conquest of Byzacena/Proconsularis and the 442 treaty with the imperial court actually meant. This is really for another time, but it seems to me that the treaty is generally reconstructed in terms of a ‘barbarian invaders/conquests’ paradigm that relies on a lot of assumptions that are not necessarily supported by the evidence itself. More importantly for current purposes, though, the patterns of African trade don’t really change after c.440. As we have seen, African traders if anything found new markets after that date and continued to trade with Italy and the south of Gaul as before, even if quantities might have declined. These issues also affect the argument that claims that the end of the western imperial command economy produced a dramatic shift in interregional connections. Logically, this ought to have happened but it does not seem to me to be readily visible in the archaeological data, in which pre-existing patterns continue, even if along (similarly pre-existing) trajectories of reduction in scale. You might not find much ARS or many African amphorae in northern Gaul in the fifth century but then you wouldn’t in the fourth either. Most of the northern Gaulish landscape was harnessed to the provisioning and remuneration of the Rhine army and it seems likely to me that, as James Harland has suggested, Britain might have also played a major role in the supply of the frontier garrisons. Consequently, the breakdown of regular government and the end of the imperial command economy is seen in the well-attested crisis in those areas, not in the patterns of Mediterranean trade.
We might also ask whether the reimposition of imperial rule is in itself sufficient to explain the startling shift in the direction of African trade in the sixth century. This seems superficially attractive as an explanation but closer reflection raises some important problems. One might, first of all, ask why the government would redirect the African annonae to Constantinople, which was amply supplied from Egypt and elsewhere already. Would/should we not see a decline in the market share of Egyptian exports if that were the case? More importantly, why would the imperial government not have reestablished the supposedly-ended (and supposedly crucial) ‘tax-spine’ to the newly reconquered city of Rome, and Byzantine Italian territories? African exports continue to reach Italy, albeit mostly (and increasingly to the detriment of other areas) Rome and in gradually decreasing numbers, until the end of the seventh century.
We might also think more closely about the ways in which wars affect long-distance exchange. Pirenne and others ascribed the breaking of long-distance Mediterranean trade to seaborne piracy, whether Arab or Vandal, but this is an implausible mechanism. Even if one were to assume that no one ever thought to provide merchant vessels with armed escorts, the relationship between piracy and seaborne commerce resembles that – in that early computer programming exercise – between foxes and chickens. If the chicken population [or seaborne merchant traffic] grows, the fox population [or profitable pirate activity] grows with it, because of the increased availability of food [loot]; there comes a point though where the fox population is so great that it is killing chickens faster than the chicken population can reproduce itself; at that point the lack of food leads to a decline, through starvation, in the fox population; eventually, however, the low numbers of predatory foxes allows the chicken population to grow again; and so on. Put more simply, you can’t have pirates without merchant ships for them to prey on. Pirenne’s thesis creates an image of a period during which Arab pirates wearily put to sea in spite of there being no shipping to attack. ‘Well, me hearties, none of us has seen a merchantman for ten years but here we go again; another day another dollar.’ The other strange point about Pirenne’s thesis is that although he thought – correctly – that long-distance trade flowed mostly from east to west, and although he thought this on the basis of texts describing imports from Palestine and Egypt, he still thought that the decisive blow to Mediterranean trade was dealt by the Arab conquests and/or by Arab fleets – creating the image of Arab pirates attacking ships that had sailed from their own ports [‘pirates on the starboard bow, cap’n!’ ‘Don’t worry lad, their ours.’]…
Be all that as it may, we might wonder how warfare affects trade. The key point I want to make is that for it to have seriously detrimental effects it needs to be ongoing for a long time. Even heavy fighting for a year or two, or a few years, is unlikely to bring about any serious shifts in trading patterns. Such events can be factored in to the usual response strategies. Campaigning by even small armies (as were the norm in late antiquity and the early Middle Ages) could produce famine but such could be responded to within the normal patterns of redistribution and relief, where they functioned. They might even produce windfalls for merchants able to sell at famine prices. More serious contenders as causal factors in long-term change are long periods of warfare such as the Gothic wars in Italy, or the wars with the Moors after the reconquest of Africa from the Vandals, or, especially, the long war between the Empire and Persia, and then with the Arabs. Such warfare is important not (or not just, or principally) for disrupting commerce, though it probably did so (though we might also remember that armies need provisioning and can act as markets) but through the disruption of production/supply and demand. Displacement of population or disruption of seasonal agricultural activities through the movement (year in, year out) of armies, associated famine and disease (plague especially from the mid-sixth century) dislocates or prevents the production of the surplus that in some way or other acts as the basis for commerce, as well as (partly in consequence) the ability for craftsmen to make the products that are traded, or the ability for markets to be held regularly with the usual security. It might be that twenty years of insecurity after Belisarius’ conquest had serious effects on some African production, but clearly it didn’t kill it off entirely. Similarly, the Gothic wars didn’t entirely end the market for African products in Italy. The wars in the east from 610 to mid-century do seem to have been fatal for the old eastern Mediterranean complex of commercial networks, production, and distribution, etc. Once again, though, we’re entitled to ask why, when the dust settled, they didn’t reemerge even if the materials being produced took different forms. Certainly, the creation of the Caliphate led to a profound rearrangement of trading networks – greater links between North Africa and the sub-Saharan world being one of the most important developments – but again, one would have to ask whether there was anything economically more logical or natural about those networks than the previously existing ones. Any investigation of that issue will lead you quite quickly to the role of attitudes, ideas, mentalité in shaping networks and connections, commercial and otherwise.
Some of the economic explanations adduced (concerning supply and demand, production costs, etc), while plausible and sophisticated, function mainly as descriptive extrapolations from data. They don’t necessarily emerge from the data themselves. Clearly, too, they are teleological extrapolations backwards from the eventual outcomes. All of this is fair enough, but the issue does need to be flagged up. And again there are some problems that arise, in my opinion anyway. One concerns the demise of the Mediterranean commercial links with the north-west. Some things from the Mediterranean were simply not available locally – olive oil is the obvious commodity here. Given the dominance of African oil production in the late imperial west, this ought to have been an important basis for commerce (and surely was). But what markets were there for this? Western towns generally contracted in size from the third century onwards but Mediterranean wares continue to be found in some north-western regions. The church’s need for oil for lighting and also for anointing, and the growth of Christianity may have provided new markets as, in the fifth century, might the new elite in western Britain wanting to show its prestige and Roman-ness. Alongside the seeming demise of the old Roman elite further to the east, this might explain the shift in the routes via which African exports entered Britain. What seems odd to me, though, is that when the economy in the north-west recovered in the late sixth century (with the revival of towns, greater aristocratic control of surplus, related increase in church foundation, increased monetisation of the economy, growing craft-specialisation, newly established markets, etc) the market share of Mediterranean products, having managed to persist through over 200 years of economic change and (especially) decline, suddenly disappeared. Imports found on sites all around the Irish Sea (east and west, north and south, rather than principally on its southern and western shores, as hitherto) seem to come almost entirely from various parts of Gaul. Descriptively one can say that more local products squeezed out the African imports but one would still need to ask why. Costs, etc, don’t seem to me to present the whole story. The whole point of my discussion thus far is, on the one hand, that normative, supposedly natural, logical, or eternal economic laws of supply and demand are in themselves inadequate to the task of explaining the changes of the fifth to seventh centuries. But so too is the notion that trade can just be ‘turned off’, like a tap, by high-level political events.
It's time, I think, to try to add some elements of ideas and worldviews to the picture to round it out (rather than replace other explanations with them). I have already said that the development of western economic systems runs to some extent parallel to some changes in outlooks and attitudes (though not necessarily to high politics or governmental shifts). This is not in itself news. Long ago it was pointed out (maybe by R.S. Lopez – I will check and correct if necessary when I have my books) that the papacy was quite happy to import Egyptian papyrus until the rulers of Egypt started stamping papyri with (to Christians) unacceptable quotations from the Qur’an. The shifts in trading routes and networks after the creation of the Caliphate are also clearly about something other than laws of economics. The demand for Mediterranean goods in western Britain in the fifth and sixth centuries was surely in large part because of the cultural cachet of commodities produced in, or somehow associated with, the Christian, Imperial, Roman World. As has been mentioned this period represents the high point of Romanitas in the region. Were easterners simply no longer interested in western trade and markets? It’s not as if there were no important commodities to be had there, and – as noted – the market opportunities ought, if anything, to have been improving. Three letters of Gregory the Great (and I am grateful to Helen Foxhall Forbes for drawing my attention to them) are significant here. Gregory is writing to the Patriarch of Alexandria who, he has heard, needs large timbers for Alexandrian vessels. Gregory could, and did, get his hands on just the sort of timber that’s wanted (in Calabria if memory serves), and get it transported up to Rome, but the Egyptians didn’t send ships that were big enough to take them, and cutting them to fit would, obviously, rather defeat the object. Gregory, it seems, is quite keen to help and to provide this timber, which obviously isn’t available in Egypt, but the Patriarch, it appears, can’t even be bothered to write back.
Thus, I would propose that an important reason (not, for clarity the reason, or the most important) for the end of any significant market share for Mediterranean commodities is that final cultural turning away of east and west after the mid-sixth century. This is a conclusion that has some important bearings on the debate upon pre-modern economies, between ‘formalist’ and ‘substantivist’ positions.