You may recall that some time ago I recorded that I had been reading David Bachrach’s Warfare in Tenth-Century Germany as part of my ongoing reworking of my paper about military service in tenth-century Catalonia.1 There are ways in which that was really useful and ways in which we are just talking about different things, but a thing that we both talk about but take quite different views on is the normal size of early medieval armed forces. Now, this is an old controversy, which goes back far beyond this book and involves names like Halsall, Sawyer and not least, Bernard S. Bachrach, and in some ways I would prefer not to get into it, not least as several of these people including Professor Bachrach (the younger) have been known to read this blog, but I can’t avoid it.2 I would confine myself to an argument that the situation I see in Catalonia, of guardposts and border-raiding and no serious armies except when an Andalusi one comes calling, is just very different from the full-on imperial warfare of Ottonian Germany, and in the article I expect that I will. But still, there are premises to the large army argument, as set up in this book at least, that I find hard to accept, and this post is an attempt at a critical examination of one of them. Where most openly stated, it goes like this:
“Ottonian military operations were consistent with warfare throughout the medieval millennium, which was dominated by sieges, particularly in the context of campaigns that were intended to conquer territory. Contrary to the long-established narrative that the Ottonian kings fielded small armies of a few hundred to a few thousand heavily armed mounted fighters (Ritterkrieger) led by warrior aristocrats, the siege operations that dominated warfare in the tenth century required very large armies, composed predominantly of foot-soldiers.3
One is, initially at least, left to assume the premises behind this. It’s easy enough to come up with some: walled cities are naturally quite large, and need a lot of defenders to keep a whole perimeter secure. If you’re attacking them, you must need more attackers than defenders, right? As it turns out, in fact, you allegedly need quite a lot more: once you get through to p. 226 you learn that, “in order to storm a strongly held enemy fortress an attacker required four to five men for every defender.” The justification for that, however, is farmed out to an article by Bernard Bachrach and Rutherford Aris.4 Now, if you actually get hold of that article, that doesn’t seem to me to be what it says: instead, by virtue of some extremely hypothetical probablity mathematics, it says that a charge by a Viking warband at a typical Anglo-Saxon burh defended by archers of the number implied by the Burghal Hidage (1 to every 1.3 m of wall) would probably have resulted in one to two attackers in every four being hit before they reached the wall.5 Even if that mathematics were somehow realistic, it’s quite a specific situation and one calculated on the basis that Vikings attacking a fortress would only have ladders to deploy so needed to make that approach.6 I don’t see how it can be transportable to a large-scale military operation with siege engines such as (David) Bachrach thinks the Ottonians were able to mount.7 Moreover, it doesn’t actually provide the numbers that he employs, only an implication that if you were to outnumber your opposing force once atop the walls you needed to allow for a fifty per cent casualty rate when planning your attack. That seems like awful odds that no commander would have risked to me, but it’s obviously not what an Ottonian planner would have been facing.

Interior view of the restored Romanesque city walls at Worms, one of the fortress cities Bachrach considers and possibly not too much unlike this in the Ottonian period? CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=167751.
But let’s take one step further back. These are figures based on the idea that victory at a siege is achieved by storming and carrying the enemy’s defences, and indeed so is Bachrach’s account of Ottonian warfare against fortifications more generally.8 But this is, surely, not the only way. More conventional, if much slower, would be simply to starve the defenders out. Now, in that case, your army requirements drop radically. Whereas before you perhaps had to have men all round the fortification, now you really only need to guard the points of access. Possibly someone could resupply a city by hauling sacks up the walls in the dead of night but not, you might think, in any real quantity, especially if you as attacker are sending patrols around every twenty minutes or so, which I assume you, as a thinking tactician, probably would be. Their supply will still not be equal to their demand. This makes siege warfare a much less demanding effort in terms of numbers; one must still be able to supply the besiegers for a prolonged period of time, but that’s easier if there’s fewer of them needed.

Even more anachronistic, but far too good a picture not to use, an illustration of a (small) siege from the fourteenth-century Codex Manesse
Of course, you still need to have more men than the defenders do, otherwise they could just sortie out and squash your forces. But wait a minute. How many more men than you do they have to have to do that before it would mean leaving the walls partly undefended, giving your troops access to the city and thus losing the war for the sake of a battle? There’s more balance here than might immediately appear, because both sides need their forces at least partly dispersed to hold their positions. The various ways that concentration of force could play out here seem to me to be very hard to calculate with and I’m not at all sure it reduces to any simple arithmetic beyond the basic logic that the more troops whom you can feed you have available, the more tactical options you have. But in a siege situation, that proviso about feeding is quite important, often for both sides.

A different (and more usual?) scale of opponent, crop-marks clearly showing a fortress, supposedly the Slavic fortress of Gana, at Hof-Stauchitz
I should say that I am not, a priori, against the idea that the Ottonians could sometimes field quite large armies, meaning in the double figures of thousands of men, although whether such were necessary for all their campaigns I rather doubt. When they were, though, they had a whole empire to draw upon and Bachrach has here a whole book full of details about how such things might have been organised, resourced, supplied and led which almost make his argument for him; one can reasonably assume that the Ottonians would have wanted to raise large armies and Bachrach shows us how they could have. But he argues it the other way around, from the necessary existence of large armies, through a reading of the sources which illustrates that, to the techniques for their provision and operation, and if these are the starting premises, they seem very shaky to me.
1. D. S. Bachrach, Warfare in Tenth-Century Germany (Woodbridge 2012, repr. 2014).
2. In reverse chronological order, more or less, Guy Halsall, Warfare and Society in the Barbarian West, 450-900 (London 2003); Bernard S. Bachrach, Merovingian Military Organization 481-751 (Minneapolis 1972), what I think of as the wellspring of the maximalist argument, and Peter H. Sawyer, The Age of the Vikings (London 1962, 2nd edn. 1971), which is the place where I first met a sustained attack on the numbers which early medieval sources used for army size. In all these cases, albeit Sawyer least and Bachrach most, references could be proliferated; a lot of Bachrach’s most relevant works are collected in his Warfare and Military Organization in Pre-Crusade Europe, Variorum Collected Studies 720 (Aldershot 2002).
3. D. S. Bachrach, Warfare in Tenth-Century Germany, p. 1, which is a good place to state your axioms after all.
4. B. S. Bachrach & R. Aris, “Military Technology and Garrison Organization: some observations on Anglo-Saxon military thinking in light of the Burghal Hidage” in Technology and Culture Vol. 31 (Baltimore 1990), pp. 1-17, on JSTOR here, repr. in B. S. Bachrach, Warfare and Military Organization, III, cit. D. Bachrach, Warfare in Tenth-Century Germany, p. 226 n. 2. A much fuller version of the argument here is however to be found in B. S. Bachrach & David Bachrach, “Early Saxon Frontier Warfare: Henry I, Otto I and Carolingian Military Institutions” in Journal of Medieval Military History Vol. 10 (Woodbridge 2012), pp. 17-60, which was presumably not available to cite in D. S. Bachrach, Warfare in Tenth-Century Germany, and would have made that a much longer book to reprise there. I engage with the version in the book here, which I assume to be self-standing.
5. B. S. Bachrach & Aris, “Military Technology”, pp. 5-10 with an appendix for the mathematics pp. 14-18.
6. Ibid., pp. 3-5, on the not unreasonable basis that the Burghal Hidage uses the same ratio for number of defenders required for places with eight-foot thick Roman stone walls (Winchester) and earthen ramparts with wooden palisades (Wareham), so the writers obviously weren’t thinking in terms of attacks actually upon the defences.
7. D. S. Bachrach, Warfare in Tenth-Century Germany, pp. 151-167, covers Ottonian siege equipment, including ladders but also mantlets, rams, ballistas, catapults and mobile towers, largely by providing detail from Vegetius and anchoring it in less-detailed reports from Ottonian sources.
8. Ibid., pp. 12-13 and repeatedly exemplified in his narrative of Henry I’s and Otto I’s campaigns provided pp. 14-69; see also Bachrach & Bachrach, “Early Saxon Frontier Warfare” for a fuller statement of the position.