Some comments on the numbers involved in migrations in the west from a previous post by Guy Halsall. I wonder if there are parallels here with possible numbers for armies from Arabia. How big could an army from the Hijaz have been?https://600transformer.blogspot.com/2019/07/reconsidering-mechanics-of-migration.html
I want to rehearse some arguments I have made before about numbers, in the military context. I am not the first to express scepticism about the numbers Roman sources give for the size of barbarian forces, yet such numbers are still routinely repeated in modern works. If we leave aside huge figures like 80,000 or 100,000 we can look at the number given by Ammianus for the Alamannic army at the battle of Strasbourg in 357: 35,000 – a number often repeated without the usual scrutiny or reservation. How likely is it that even a confederacy like the Alamans could put together an army that size?
One can think comparatively. Armies of that order of magnitude were not common in better-documented eras until the seventeenth century, although they are certainly attested in the late middle ages. The largest recorded muster of the medieval kingdom of England was just over 32,000 men, in the 1340s. One might mention, in contrast, the capacity of the Zulu kingdom to put armies of over 20,000 men into the field but it must be remembered that these armies assembled quickly, in a different sort of terrain and political structure, and dispersed equally quickly. Could the Alamanni have done something similar? It is worth considering how this could have happened but we need to think hard about those mechanisms and not simply assume them. Such an army would need, like the Zulu, to assemble, fight and disperse quickly. For the Alamanni, a point can be made here, to which I will return: the presence, in however decayed condition, of the Roman road network in the former Agri Decumates, which, perhaps would allow a large army to assemble quickly. Such a force would nonetheless not be sustainable over a long campaign.
The reason for that is logistical. The largest settlements in Iron-Age Germanic-speaking Barbaricum had populations numbering only hundreds. In other words, the economy of Germania Magna was not geared to the provisioning of large numbers of people. An army of 35,000 men would be a population group seventy times the size of the largest settlements in Germania. Historically, armies have sometimes been more numerous than cities; the English muster of 32,000 in 1347 – if they were all gathered at the same place, which is not entirely clear – was two or three times the size of most of the larger English cities, though still be smaller than the estimated population of London at that date. But not seventy times larger…! For that ratio Edward III would need to have assembled something like 700,000 men. The larger late medieval armies were, moreover, raised in urbanised societies with fully monetary economies and complex market, trade and supply networks and systems, taxation, better agricultural techniques with greater yields and so on: things not available to a fourth-century barbarian polity.
Moving of 35,000 men through the late antique landscape – on either side of the Rhine – would consume the grain supplies and livestock of entire communities every day, producing famine, and probably still going hungry. The late Tim Reuter described the effect on the ninth/tenth-century landscape of an army of 20,000 men as equivalent to the down-wind fall-out ellipse of a nuclear explosion; it’s an image worth remembering, not least because the socio-economy context of Carolingian Europe offered more possibilities for supporting a larger army than did that of Iron Age Germania.
A much smaller army, say 10,000 men – or less – could be catastrophic for the population of the regions through which it moved. To see the sort of devastation wrought on Roman provinces that is sometimes attested in the written sources does not require us to envisage enormous invading hordes.
The solution to these problems would be for individual contingents to bring their food with them. How many days’ supplies could be transported by a warrior? With baggage animals, the amount increases but, as the classic studies of military logistics have demonstrated, the demand for fodder and food for the animals’ attendants grows parallel to the number of baggage animals. Charlemagne expected his warriors to bring food for three months’ service in the early ninth century. Again, while that is an interesting comparandum, one needs to take account of broader context. Charlemagne’s was a much more complex and well-organised realm than any in fourth-century Barbaricum: urbanized and monetized to some extent. He also enacted at length about supply carts, package animals, the preservation of fodder for passing troops and the maintenance of bridges and boats. The law about a three months’ supply also applies to the caballarii of a monastery, mounted troops supplied from a large land-owning establishment. Indeed, Charlemagne envisaged that the resources of four farms were necessary to furnish a single warrior. How much of this can be applied to Iron-Age barbarian armies? We would need much better evidence than we currently have before we could assume that much of it was applicable in detail. Charlemagne’s field armies were almost certainly much smaller than 30,000 men. Karl Leyser suggested that such armies were fed as much by cattle on the hoof as by waggon- or pack-horse-loads of grain; this might apply to barbarian forces too. If so, however, issues about fodder and ease of movement across difficult terrain are emphasised.
It’s nonetheless worth remembering that in the 350s a force of 600 Franks caused Julian serious problems. There’s no logical reason to suppose that Roman writers were more likely to be telling the truth when they mentioned low numbers than when they recorded very high ones but we might accept that this was a ‘small’ force. The Romans defeated it by starving it out. Before that, it can have done enormous damage. Six hundred warriors would be more than entire Roman communities outside the towns and could move rapidly, consuming settlements’ bread, killing and eating the cattle they were saving for winter, murdering anyone who objected, raping and/or enslaving women and children with impunity. If a couple of Roman field army regiments caught them, the game would be up and swift punishment meted out, but it’s vital remember the damage and trauma even a small raiding force could cause. Let’s not sanitise this!
This has important implications for barbarian migrations that have rarely been discussed. How feasible was it for a barbarian ‘horde’ of 20,000 warriors plus families and followers – up to the number of 100,000 frequently found in modern discussions (including mine) – to travel any distance or for any length of time?
We must ask serious questions before repeating the numerical estimates that have become almost canonical in the literature. My paper is mostly about asking questions – frequently quite obvious ones. Many are unanswerable, in some cases perhaps only in the current state of our knowledge but in others they concern things we can never know. Nonetheless the existence and importance of these questions need to hang over future discussions of migration. We can’t simply assume things. We can’t be afraid to challenge age-old consensuses, to point out the difficulties in making assumptions or to admit there are things we can’t know.