This week, we’re going to talk about armor effectiveness, comparing the value of body-armor before gunpowder with what gets portrayed in fiction and broader pop culture. What does it take to defeat armor? What weapons were effective at defeating armor – and what kinds of armor were they effective against? I should note that I am going to focus here on armor-types common in Europe (c. 200 BC – c. 1600 AD), because that is where I specialize, but the basics of this analysis could also be applied to armor elsewhere (at least for armor made of textiles, iron and steel).
Let’s begin with the trope as presented in media. Pop-cultural depictions of armor often show plate armor being defeated by arrows:
Or by spears:
Or sword thrusts:
Or…sword cuts?
Or axe blows:
I trust I have made my point. If you truly do need more examples, TVTropes will provide.
I suspect we can all recognize these examples as a bit silly. Armor obviously wasn’t this useless, or no one would have worn it. But accuracy here is a narrow path with traps to both sides – just as much as I have had students assert armor penetration from weapons which probably couldn’t (particularly the longbow, to which we will return in a moment), I have also had students assert armored invulnerability in situations where it probably wasn’t. So where does the truth sit?
In simple terms, there are two main variables here: the type of defense, and the type of attack. Armor in the Middle Ages was often worn in layers, with a textile defense base layer (a gambeson), then a flexible metal defense (mail), followed by surface rigid defenses (plate, coat of plates, brigandine, etc) – don’t worry if that doesn’t make much sense, I’ll explain the layers a bit as we go on. We’ll look at how each layer performs against a range of potential attacks. That’s going to be math-and-example heavy, so if you want, at the end of each section, I’ll have a paragraph labeled UPSHOT in all-caps and bold like that, where I’ll sum up what it means.
Also, I am going to refer quite a bit to one work, Alan Williams’ The Knight and the Blast Furnace (2003). For the sake of brevity, I’m just going to note it as Williams (2003) (or just Williams) from here on in. It represents some of the best and most recent work on the metallurgy of armor and features an extensive section on defeating armor. Alas, it is not the sort of book priced for mortal men or that one can find outside of university libraries. That said, we will part ways with it on a few points.
Alright, with that preface done: onward!
Bottom Layer: Textile Defense
Alright, first, what do I mean by textile defense? A gambeson (also called a padded jack, arming doublet or aketon and possibly the same as the Roman subarmalis) formed the base layer of effectively all medieval armor. For very poor soldiers, this may have been the only defense available to them for the body; for wealthy knights, their gambeson would have attachment points for the rest of their armor (this is what would make it an ‘arming doublet’). A gambeson was made by sewing together (quilting, really) several layers of thick textile (usually linen or wool).
This construction poses two obstacles to an attack: first, any kind of piercing or cutting attack has to defeat multiple layers of textile before reaching the body. Second, the tiny air-pockets created in the quilting, along with the textile itself, creates a cushion against blunt force trauma and also serve to absorb some of the energy of a blow.
(Note: There are other forms of textile defense. Most notable for me is the Greek ‘linothorax’ (on which the best book by far is Aldrete, Bartell and Aldrete’s Reconstructing Ancient Linen Body Armor (2013)), which was probably a layered, laminated textile armor. Unlike a gambeson, it had no air-pockets, and was quite rigid. I’ll talk about it more in a future post.)
Williams (2003) is less focused on organic defenses (horn, leather, textile), but his experimentation with them still provides a solid starting point for discussing the gambeson. Williams measured armor resistance in terms of the energy of impact (measured in joules, J) which resulted in defeating the armor (defined as a 40mm penetration minimum).
I want to stop for a moment and discuss this method, because on the one hand it is some of the better documented testing done in print, and on the other hand, it has some limitations. The largest of these is that Williams has broken his tests down by the type of weapon used (blade, lance, arrow, bullet), using simulated blows where the precise energy of impact could be assessed (meaning he did not hit them with actual weapons, as I understand his method). This is good for data, but it must be noted it presents those weapons with what are essential ideal penetration circ*mstances – the armor is not moving, struck dead on, etc.
Also, because of Williams’ research focus (on metallurgy, especially for plate armor), the number of tests of mail and textile were understandably fairly few – they served mostly as a benchmark against which to assess plate defense. Fabrics other than linen (wool, silk) were not tested, nor mail with different join methods (riveted against end-abutted or welded mail) or ring-sizes. Given that his book is already near a thousand pages, we ought excuse him for not having gone further!
Against a blade, Williams rated 5mm leather armor at only 50J, buff leather at 70J and proper cuir bouilli (all at 5mm thickness) at 90J. In contrast, a 16-layer linen padding (suitable to be worn under armor), rated 80J, and a heavier 26 layer quilted jack at 200J. For comparison, Williams estimated the normal force of a sword or axe blow around 60-130J, which suggests that a sword or axe may or may not defeat a gambeson with a cutting attack.
(As a side note: this should quickly put to rest the idea of using normal, tanned leather as a primary defensive material (as so often appears in fantasy games), or that leather armor which did work was ‘light.’ Cuir Bouilli is not like the leather in a jacket – it is thick and hardened to the point of being little more flexible than an iron plate. It is also fairly heavy. That, not modern biker-wear, is what ‘leather armor’ generally consisted of – with some room for exceptions, of course.)
However, against a piercing or penetrating attack (like a lance or an arrow), the organic defenses fared much more poorly. The 16-layer padding managed to resist only up to 50J behind a spear-point, while the cuir bouilli failed at just 30J. This is a real problem against things like arrows and crossbow bolts, which might arrive at anywhere from 80 to 200J, well above the defensive power of the gambeson.
You can actually see a set of tests that produce consistent results to these done by Youtube Armsman Skallagrim here. Dull swords and poor strikes fail to penetrate the gambeson they are testing, but solid blows from sharp swords cut through and often deeply. Thrusting attacks penetrate deeply and with ease.
The UPSHOT: If a gambeson was all you could afford, it was a lot better than nothing. Assuming you kept moving and made yourself a hard target, there was a good chance that this kind of armor would resist a sword cut or an axe-blow, or at least limit the depth of the cut to something less than lethal or debilitating.
On the other hand, there was also a good chance a solid cut would cut through and open a nasty laceration. Moreover, the chance of a gambeson stopping a well-placed spear-strike or a lucky arrow was very low. This in turn, starts to hint at why shields were so important to medieval combatants – arrows are very hard to armor against (as we’ll see), but a solid shield could offer protection against missile fire.
So, if you are planning your fantasy or historical fiction series and you have someone in just a gambeson who falls in battle, you can bring him down in almost any way – but a thrusting attack from a spear or sword is more likely to do the job than a cut. But unless you have a legendary hero delivering the cut, the blow ought not take a man in half if he’s wearing a gambeson – it does offer significant resistance.
Middle Layer: Mail
Mail – sometimes called chainmail or ringmail (note that when I say mail, this is what I mean – terms like ‘scale-mail’ and ‘plate-mail’ are modern creations, inaccurate and confusing) – is armor made of interlocking metal rings, typically arranged in a 4-in-1 pattern, alternating solid rings with rings that are either riveted or ‘end abutted’ (meaning open rings bent closed). Mail armor was developed in Europe during Antiquity (by the Gauls), so it predates the European Middle Ages – it was, in fact, the preferred armor of the Romans for the period of the Late Republic.
(Note that for this and the following section, I am assuming iron or steel as the material. The Romans did make copper-alloy (read: bronze) mail armor. Some armor rings of this type were recovered from the Roman camps at Numantia, for instance. But most mail was made from iron, so that’s what we’ll look at.)
Mail was, however, expensive. Constructing a mail shirt might require producing as many as 40,000 (or more) iron rings, which then had to be joined by hand. This is quite labor intensive. Any kind of worked metal in the pre-modern world is likely to be expensive when new, as the forging process required not only skilled labor, but also a lot of fuel. Adding labor intensive construction only increased cost. Mail’s advantages were considerable though: the armor is flexible and not too heavy (c. 4-8kg for body armor covering from the shoulders to knees).
Mail armor is likely to fail in a very particular way: the rings can be split. On the other hand, cutting mail is functionally impossible in combat conditions. Williams (2003) conducted experiments with two pieces of mail, a modern replica and a 15th century mail gusset. In both cases, the energy required to defeat the mail with an edged weapon (like a sword or an axe) exceeded the roughly 130J upper limit for hand-held cutting weapons. Indeed, the mail was somewhat damaged but undefeated by a 200J blow from a halberd. A warrior will sooner inflict blunt trauma through the mail than he will cut it – and indeed, this is exactly why weapons like maces became popular as mail armor became more common during the High Middle Ages.
(Note: I have heard and read reports or mail armor rings being burst, which is not quite the same thing as cut. Here what I’ve seen reported is that the force of a sword-blow has burst the rivet in a riveted mail ring (or several), opening the rings and thus weakening the armor. I should note the word ‘reported‘ – I have not seen this form of damage done with an edged weapon myself. It’s not clear to me that this damage would allow the weapon through.)
On the danger of splitting mail, however, we must part ways (at least a bit) with Williams (2003). Williams places the energy required for a spearhead to split mail at 140-200J, noting that his simulated lance was unable to really defeat the mail decisively. This would suggest mail was a very solid defense against a spear. From a historical perspective, this seems unlikely – spear-points penetrating mail are well reported in the historical record (e.g. Plut. Aemilius 20.4). Lance strikes through mail are also fairly common in medieval artwork. Moreover, a number of members of the enthusiast HEMA community have also tested this, and have produced mixed results, but quite a few clean penetrations which would have done serious harm (e.g. tests by Skallagrim, ThegnThrand, and Roland Warzecha).
In this case, I am quite curious as to the shape and design of Williams’ simulated spear point (he calls it a lance point), as well as the treatment of the iron. For penetrating mail, hardness (as in the metallurgical trait) matters a lot – a soft metal will blunt or bend more readily, whereas a harder metal will hold its shape better, forcing the ring to resist more energy or split. Shape also matters a great deal – note in the videos above how much more successful Skallagrim’s 12th century ‘winged’ spear is than Thrand’s ‘Celtic’ spear – the former has a narrower, more sharply tapered tip and thus can get through with a lot less energy, because it has less material to push out of the way.
(Pedantry note: ‘Celtic’ is terribly imprecise – on the problems and limitations of this term as used to describe these people, note S. James, The Atlantic Celts (1999). It is true that the Greeks classified a broad swath of peoples living from Anatolia to Spain as keltoi (Celts). But those ‘Celtic peoples’ did not have a single material culture or a single set of weapons (weapons in Spain and Britain look quite different, in fact). In this case, I think using the archaeological term for this material culture group – ‘La Tène’ – or the geographic term – Gaul and Gallic (which, yes, is what the Romans called them and has its own problems) – is probably more appropriate and precise. In either case, Thrand’s spear looks to be a faithful reproduction of a La Tene Type IIIb (following Brunaux and Rapin’s typology from the deposit at Gournay-sur-Aronde (1988)). That type was never very common, but most popular c. 300 to c. 200 BC.)
It is interesting to see how the variables in these tests – the force of the blow, the quality of the mail, the spear-head shape, and the resistance of the target – impact penetration. Notably, penetration seems to be much less likely for a target that can ‘give’ behind a blow like a human would be likely to, as it robs the thrust of much of its power. Unsurprisingly, heavy blows (either striking from above or with two hands) perform better, as do narrower spearheads. In any event, the tests do confirm that a spear could penetrate mail, although it was by no means guaranteed to.
The other threat to splitting mail came from arrows and crossbow bolts. Williams (2003) notes that using a simulated bodkin arrow, the rings were split at 80J, at 100J, they were split with enough force to penetrate the padded jack underneath and at 120J, the mail failed utterly. Such hits are within the capacity of the bows and the crossbow Williams tested, although the bows he used – at 80lbs pull – would be by no means the hardest hitting of war bows.
It’s worth noting that arrows can carry more than one kind of point (technically the point of a war arrow is in fact, a warhead). Against textile or flesh, the standard arrow point was a ‘broadhead’ – often with barbs to make it difficult to remove. But precisely because this was broad, it wouldn’t split the rings of mail. Instead, the ‘bodkin’ point – a narrow, square-sectioned (think ‘railroad spike’ shaped) sharp point was designed to defeat mail. As armor got stronger (see the section below), another arrow-tip type, a shorter, less sharp version of the bodkin was developed – we’ll talk about that below.
For more detail on arrowhead types (including crossbows), I strongly recommend this video as a great quick primer.
I want to come back to questions of aerodynamics and range in next week’s post, so I won’t dwell overmuch on those questions here. Likewise, I’m not going to deal with guns here, check back next week!
I do want to note that there is considerable room in mail for quality differences as well. Mail constructed of smaller rings (you will need more of them) puts more material in the way of an incoming strike and is thus harder to defeat (but much more expensive). Riveted mail is much stronger than mail made of end-abutted rings, which can simply be bent open. A strike which lands on a riveted ring, compared to a solid ring, is also more likely to succeed, though this is mostly a matter of luck. Finally, the quality of the metal also matters a great deal.
UPSHOT: As Williams (2003) notes, a man completely armored in mail (like a knight of the 11th or 12th century) could content himself that he was largely immune to cutting attacks. Against penetrating weapons, he was more vulnerable – a solid spear-thrust or an arrow or crossbow bolt at close range was a danger to him. At long range (we’ll talk about this next week), he could be much more assured of safety.
As will become clear, when we talk about things like bodkin arrowheads and crossbow bolts as being ‘armor piercing’ it is this ability – to split the rings of mail, that we mostly mean. Given that threat, is it no great surprise that knights of this period do not yet abandon their large shields. The knights of the Bayeux Tapestry, for instance, are fully armored in mail, yet continue to carry their heavy kite shields.
I should note here that as mail becomes more common again in the Middle Ages (it had become somewhat rarer after the fall of the Roman Empire), weapon design shifts to challenge it, with swords tapering to finer thrusting points and narrower spearheads designed (probably) to defeat mail. This is a common thread in weapon design: weapons and armor evolve in relation to each other.
So if you are designing your historical fiction or fantasy battle, and you need to be bringing down a load of bad guys in mail armor, what we’ve learned is that your hero shouldn’t be cutting them. Thrusts from swords or spears, arrows or crossbows – or good old bludgeoning attacks from a mace – these will be your best bet. But the edge of a sword (compared to the point) will do little against mail armor.
Plate Defense
I am going to compress a number of plate-type defenses into one category here. The full plate harness of the Middle Ages developed out of transitional armor types that consisted of a number of smaller plates (coat-of-plates or the brigandine). But the defensive principle remained largely the same: a solid plate of iron (or steel).
Plate defenses varied wildly in thickness, along with the quality of material. Some of the thickest cavalry armors of the 17th century were as much as 8mm thick (this was ‘armor of proof’ designed to resist musket fire). On the other end, ancient armorers generally contented themselves with thicknesses under 2mm and often under 1mm, even when working with bronze. Thickness also varied within a single full plate harness: the crown of the helmet and the breastplate itself are generally very thick, but arm and leg protections might be quite a bit thinner (one harness noted by Williams (2003), has a helmet crown of 1.5mm, and a breastplate 1.3mm thick, but the leg protection is only 0.7mm thick, for instance).
The angle of attack also matters a lot more with a solid plate. Whereas mail and textile provide a surface an arrow can ‘bite’ into, there is a huge difference between a dead-on hit and a glancing strike for a steel plate. A strike at a 45-degree angle might require a third-again more energy in order to achieve the same penetration against a target.
The energy required to defeat a steel plate rises geometrically, not linearly, as the plate gets thicker, as Williams (2003) notes. In practice, a steel breastplate of decent (even just c. 2mm) thickness was functionally immune to handheld weapons and bows and crossbows except at extreme close range. You can see an example here of a high poundage (quite a bit higher than the 80lbs bows used by Williams in his test) longbow being shot into a steel breastplate at point-blank range. The breastplate is secured to the ground and there is no additional protection behind it – in terms of range, power, positioning this is an absolute worst-case test for the breastplate. It is barely scratched.
Crossbows can do somewhat better. Skallagrim tested a crossbow against both a lamellar (layered metal plates) armor and a breastplate – both of admittedly low quality – against a 350lbs crossbow and a 975lbs crossbow. While they are able to dent and punch holes in the breastplate, neither defeats it in a way that would wound a person wearing it. Range matters a lot – and these were fired at extreme close-range for the weapons.
The consequence of this, as Williams lays out, is that penetrating steel plate requires practically impossible quantities of energy for a bow or crossbow (but not, potentially a firearm – more on that later). Even a straight-on hit for an anti-armor arrowhead would need to deliver some 175J of energy to defeat just 2mm of armor. But armor was designed such that straight-on-hits would be extremely rare – armor surfaces curved and sloped away from the direction of attack to encourage blows to glance off. Williams figures the upper end of crossbow energy delivery around 200J, and that at absolute point-blank range. Except for an absolute dead-on shot, even this would be insufficient.
Thus, as Williams (2003) notes, a knight in a full 15th century Milanese harness could be confident that functionally no arrow or crossbow would be able to penetrate his armor (at c. 2mm thickness). A spear couldn’t deliver the same amount of energy – both the bow and the crossbow benefit from being able to store energy during the draw and release it into a single shot, whereas the spear is only accelerated for a short time and thus doesn’t deliver as much energy on impact (again, Williams has the experimental data, if you are curious). Thus with a wider head and less energy – a spear won’t pierce what a crossbow couldn’t. Assuming that knight remains standing and protects the vulnerable gaps in his armor – armpits, groin, neck chiefly – he is effectively immune to most of what a spear-wielding opponent can do to him.
This is not to say that a plate-clad warrior was beyond fear. The era of the plate harness also saw the emergence of weapons designed to defeat it, either by striking at the gaps in the armor with mail-splitting weapons (like the rondel dagger), or delivering blunt force trauma through the armor (warhammers, maces), or by wresting the enemy to the ground where a precise thrust could be given to a gap in the armor or the armor defeated by a powerful descending blow.
It’s also worth remembering that not all parts of the armor were equally strong. While the center of the breastplate might be almost invulnerable, other areas were more so. Fiore de Liberi, for instance, shows several ‘plays’ with a poleaxe aiming blows at the visor to disorient and ground the opponent, or at the sides of the helmet to wound him. Visors in particular tended to be vulnerable, as they needed many small holes to allow the knight to see and breath, which not only provided entry-points for smaller weapons, but also weakened the overall structure of the plate, allowing it to be defeated by high energy weapons. A crossbow bolt that would bounce harmlessly off of the breastplate might well push through an eye-opening or a breath (bending the thinner plate as necessary), with lethal results.
Finally, I should note the existence of short, stubbier versions of bodkin point arrowheads for both arrows and crossbow bolts. These were a response to plate armor. But as the video I noted above (where Tod of Tod’s Workshop describes the arrowheads) they weren’t capable of punching through breastplates – that wasn’t the point. Instead, they could potentially penetrate the much thinner plates of things like visors. That may seem unlikely, but remember that they are being fired in mass volleys – someone is bound to get lucky. And if you miss a mounted knight – there’s a good chance you’ll hit his horse. There’s a reason the French learned to attack on foot in the later stages of the Hundred Years War (e.g. Agincourt, 1415; Formigny, 1450, though that isn’t to say they stop using cavalry).
UPSHOT: Showing blows penetrating through plate armor – a depressing commonplace in portrayals of both fantasy armor and historical armor – should, in fact, be very rare. Even at extreme close-range with high-poundage war-bows, penetrating plate armor is almost impossible. Very powerful crossbows at very close range might do it, especially against low quality armor, but even then, the odds are in favor of the armored man.
The more likely way for a warrior in a full plate harness to fall is a strike to a vulnerable point. Wounds to the face from arrows and crossbows are not infrequently reported. The armpits, groin and neck are also difficult to protect with plate armor and thus were key vulnerabilities that might be aimed for. But a well-made plate harness of the sort an upper aristocrat (like a high noble) might have – in a society that produces such armor – is unlikely to be defeated by a puncture of the steel plate.
Ending Rightly
This hasn’t been intended as a complete list of battle tactics against enemies in armor. Almost every weapon available in the Late Medieval period probably had some response to an opponent in armor. Many of these alternate tactics survive in fencing manuscripts from the period – practitioners of the longsword will be familiar, for instance, with half-swording, morte-striking and grappling.
Rather this was an exercise noting the effectiveness and limits of armor. At each stage of ‘up-armoring’ our combatant, survivability improves markedly. It’s not hard to realize why armor was worn, despite the weight and other drawbacks (we’ll talk about that in a future post, I have no doubt). Even the humble gambeson offers a tremendous jump in protection compared to simple clothing.
But I think there are some key take-aways that deserve noting:
First: The protection afforded by armor does not increase in some linear fashion. I think, influenced perhaps overmuch by war-gaming, there’s a tendency to want to reduce ‘armor’ (and ‘armor penetration’) to a number, a ‘damage reduction’ figure. But that’s just not how the protection works. Upgrades in armor effect different weapons very differently. Mail makes pure cutting weapons practically useless, but offers very limited protection enhancement against arrows compared to a gambeson, or even nothing at all. But it is not as if the bodkin arrow merely has ‘+1 armor penetration’ given that a full plate harness suddenly makes the arrow far more useless than the sword or the axe (which can at least disorient the target and – in the case of the sword – thrust through vulnerable areas).
Second: Armor was useful. With some notable exceptions, anyone who expected to be on a battlefield wanted to have as much of it as they could. Examples where heavy armor was ‘traded down’ for the sake of being ‘nimble’ (as we often see in movies and games) exist, but are very few (switching out helmets for more vision or air is more common). Preferences for certain kinds of transitional armor (brigandine, cuir bouilli over mail, etc) over a plate cuirass seem more common. The key exceptions were men who did not expect to be in close-combat – archers are often (but not always!) shown unarmored, as were men working siege equipment. One assumes that the issue here is the heavy physical exertion (or cost – these are, after all, not aristocrats), not the need to preserve a ‘dex bonus.’ To reiterate, if you could afford better armor, the vast majority of the time, you did.
Third: the way many movies and games show armor being defeated is silly. But I think most of you knew that before you started reading. So why do they do it? I strongly suspect the issue is safety. If you are filming Helms Deep, sure it’s more realistic to tell your factors to aim for the orc’s exposed faces rather than their breastplates, but that’s also a great way to send a few extras to the emergency room. A lot of stage fighting is like this (like that move you see everywhere where the hero swings his sword lightly into contact with the extra’s belly, holds it there for a second, and then draws it to the side rather than completing the cut in a single, smooth movement – this is presumably so you do not hurt your extras).
Finally: the way armor and weapons evolved in competition with each other had important battlefield effects, which in turn rippled out into the larger society. To put the point in a very schematic sense (to which there are many caveats), the development of armor over time tended to increase the battlefield advantage of the well-equipped, well-trained man over the poorly-equipped, poorly trained man. Armor made the knight increasingly resistant to the sort of weapons his ‘social inferiors’ might have access to. It is no accident that this general trend coincides with the same class of military aristocrats consolidating a greater hold on society. It is also no accident that the development of weapons and tactics which diminished this advantage coincided with the reverse.
(For the world-builders out there, a bit of advice: think about how the armor and weapons of your world interact. Weapons should have an intended or ‘ideal’ target. There’s little use for a military pick, warhammer or rondel dagger in a society with very limited armor. Likewise, a warrior expecting to face armored opponents should probably bring a weapon fit to deal with them. The armor a society uses should respond to the weapons it faces, and vice-versa.)
Next time: We’re going to tackle a related topic – missile weapon ‘kiting’ and how range impacts the striking power of bows, crossbows and even muskets.
