The barrier while active would keep anything from making contact, but force could still be transferred.

Its not always on and can be "drained" from multiple blows. Approximately 20 full strength blows from an average male using a long sword.

Unlike real armor there are no gaps and a point of the armor could only become weaker than another point by a user deliberately shifting energy around themselves. The rate at which energy can be would vary from person to person, but let's say that an average soldier would do it in half a second plus their reaction time. Energy would be drawn equally from all parts of the barrier.

The power of these barriers varies from person to person. It can be strengthened throughout life with repeated strenuous use.

The barrier can be bypassed by piercing and averages around the difficulty to pierce as Steel plate armor.

Energy such as heat can still affect someone though the barrier.

All liquids and solids would be blocked by the barrier unless the user allowed them through. Gases with enough understanding could be specifically blocked, but are mostly all allowed through in order to let the user continue to breath.

  • $\begingroup$ How strong is this barrier, would it stop any kind of medieval weapon? How many blows (on average) would it take to break it? $\endgroup$ – Alexander Nov 1 '17 at 16:22
  • $\begingroup$ I was thinking it would be around the protective ability of plate armor. It would of course eventually dissipate. Let's put an average of... twenty swings from a Long Sword with full reckless strength from an average adult male. I realize Longsword is more of a category than a specific sword, but it is generally known and would be an example of a weapon I cannot imagine would be effective in this world. going to add this to the main post. $\endgroup$ – Azohn Nov 1 '17 at 16:27
  • $\begingroup$ It won't change anything if the enemy poisons or subverts your magicians. $\endgroup$ – user535733 Nov 1 '17 at 17:17
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    $\begingroup$ This question is too broad. Even if we assume that by medieval you mean medieval european, the middle ages had a very diverse range of weaponry and styles of combat that occurred within them. The important thing to understand about the design of weapons and armor is that context is everything. Without a specific context this question is unanswerable. $\endgroup$ – sphennings Nov 1 '17 at 18:21
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    $\begingroup$ Does your magic barrier affect air flow? How does it work to stop conventional weapons? If the air flow is obstructed one could just keep bombarding a shielded person till they suffocate. If not, poisons would rein battlefields, especially liquid and gas types. $\endgroup$ – Olga Nov 2 '17 at 3:43

10 Answers 10


You would see a massive shift away from medieval spear formations and a heavier focus on what we would call Medieval Anti-Armor tactics. In short: Don't try to pierce the shield...hurt them despite the shield.

Historical Background

In the middle ages, most people on the battlefield weren't running around in Full Plate. Full Plate is expensive, time-consuming, and difficult to craft. A full suit of Plate Mail could take months to craft. Instead, most people who were 'armored' wore a simple Breastplate and/or a mail shirt, along with a helmet and whatever arm and leg protection they could get.

So, most of the time, you didn't need to worry about hitting someone in a way that breached their armor, you just had to hit them somewhere their armor was weaker. This (coupled with the ease of training people in their use and how easy/cheap they were to make) is why spears were so popular in medieval infantry formations. You get to stay nice and far away from your enemy and stab at the spots that aren't covered in a sheet of steel.

Where this becomes a problem is when you have someone in Plate. A Plate Mail wearing soldier was practically a dreadnought on the battlefield. Spears, swords, axes...practically any cutting or thrusting weapon melee would just bounce off. For a while, the Longsword was able to penetrate plate with a really strong thrust but as metallurgy got better and plate was made thicker...even that stopped working.

This was the point where, when fighting against heavily armored targets, swords stopped being used on the battlefield. Cutting or piercing plate mail was practically impossible without a polearm (such as the piercing spike on the back of a Halberd) and enough space to swing it. So, you stopped trying to pierce the armor, and you just tried to wreck the guy inside of it without breaking the metal.

Thus: maces, warhammers, and other bludgeoning weapons became the more common weapon used for anti-armor combat. The goal wasn't to penetrate armor, it was to hit someone so hard that it hurt them right through the Plate by transmission of Force. It doesn't matter if your helmet can survive the blow, if your skull experiences a massive enough abrupt change in velocity it will give you a concussion. Hard enough, that might just kill you.


As you have mentioned, the personal shields do not negate forceful impacts. Thus, you would use weapons designed to deliver maximum impulse to your target. This would mean a warhammer, mace, war pick, or other heavy weapon that has the vast bulk of its weight at the striking end.

The goal here, as with dealing with someone in Plate, isn't necessarily to penetrate the shield.If you can, awesome! But, mostly...it's to hit them hard enough that the force of impact is conducted into the body--dealing damage right through the shield.


Armor would still be useful in this case, but it would be...potentially weird.

If you can design armor such that it sits outside of your shield, then you can add bits designed to deflect impacts away from you. Later designs of Plate Mail had features like this to help mitigate the risk of blunt weapons. The human body (and thus, presumably, the shield) lacks these contours, so a blow to your chest would have the full surface area of your torso to hit. If you designed armor that was curved around your chest, then an indirect blow might glance off the side.

If you cannot design armor to sit outside the shield, it may still be useful as a back-up. In this case, armor would still be basically exactly what it was before. Perhaps with a focus on padding and support to try to mitigate some of the impact you take.

In either case, physical shields are still useful. A hit taken by a sturdy piece of wood is a hit not taken by your personal shield. And blunt weapon blows to your wooden shield can be absorbed by the flex of your arm...instead of being taken directly into your body.


Volley Fire from archery weapons would not exist. How reliably heavy archery weapons could penetrate plate armor varies depending on who you ask (and how thick they believe plate armor of the day was). I won't try to go into too much detail here--but we'll say it's theoretically possible for a strong enough bow to penetrate the shield.

The problem is, naturally, the further a projectile flies the more speed it loses. And the faster a projectile is moving when fired, the more drag it produces (equation to compute Drag Force squares the object's velocity). Tests I have seen that show a bow able to pierce Plate has the weapon being fired at practically point blank range (usually within 30-40 feet). Thus, the odds of an arrow maintaining shield-piercing velocity by the time it flies all the way across a battle field in a high arc is practically nil.

In the middle ages, Volley Fire was useful because you could just throw a massive number of arrows at the enemy and, since most of your enemy wasn't wearing full plate--you'd probably hit plenty of unarmored or weakly armored spots.

If archers were to be viable, it would have to be straight-fire at relatively close range (for example, archers atop a castle firing down at invaders at the walls).

In fact, it is questionable whether or not archery would have taken off at all. Early bows would have been utterly useless against shielded targets--so it is uncertain whether or not the development of the Warbow or Heavy Crossbow would have happened at all.


The Lance of a Mounted Soldier was, essentially, the most reliable way to penetrate armor while still maintaining tight formation. There are numerous accounts of blunted lances still piercing through jousting armor which was over-engineered to be as heavy and sturdy as possible. You wouldn't wear jousting armor on the battlefield because it was too hard to move in.

The amount of force delivered by a couched lance striking you, propelled forward by a charging warhorse was enormous. Even if you took an indirect blow and it didn't penetrate your personal shield, it would still knock you over with significant force.

In the same way, as your Personal Shield does not protect you against the force of impact...the sheer blunt force of a Heavy Horse Charge slamming into infantry would still be devastating. Soldiers get bowled over, trampled, knocked into each other, lose their weapons, and so on. It may not kill that many people, but it would shatter your formation and probably terrify any conscripts you had in your ranks (getting run over by multiple horses would be a very scary and deeply unpleasant experience even if it didn't break your shield). If you couldn't get your formation back in order before enemy infantry closed with you...you're history.

Cavalry archers would likely not exist. As you said, a personal shield tanks piercing damage about as well as steel plate. It takes a heavy bow to pierce steel plate--significantly heavier than what you can use from horseback. Chariot Archers may still be viable, if armed with heavy crossbows or warbows...and a Chariot would still do a fantastic job of running people over.

Thus, melee cavalry would still see a lot of use. Even a lighter horse carrying someone armed with a warhammer is still going to make that warhammer hit significantly harder if the rider hits you while he rides by.


This 'personal shield' would also change tactics on the battlefield.

Troop Rotation

A 'standard baseline' would be established of how much abuse a single person's shield could generally take. You'd then estimate that out based on time in combat, then you'd rotate out troops to put 'fresh shields' on the front line in the same way that a shield wall would rotate troops.


A skilled enough warrior may be able to prevent you from getting a 'straight shot' at him with a blunt weapon. This is especially true if you're dealing with peasant levies or other forms of conscripted troops who have minimal training.

So, your goal becomes similar to how footmen would deal with a Mounted Knight in the middle ages.

Step 1: Put him on the ground. Step 2: Dogpile with weapons.

A similar tactic could be done on a grander scale to allow less skilled combatants to still be effective at fighting. For this, you equip some of your troops with Lucerne Hammers as their 'primary weapon,' mixed in with the soldiers with traditional warhammers and maces.

A Lucerne Hammer has both the hammer on the end of a long pole for massive striking power, and also a hook on the back--which can allow you to catch the legs of an opponent to pull them off their feet.

So, the tactic for these troops becomes: Use the hook to sweep an opponent off their feet, then bring an overhand downward blow with the hammer side. Or simply let your allies dogpile the guy on the ground. Impacts are still a thing, so someone on the ground will have a really hard time getting up if a bunch of people are pounding on them.


Weapons and tactics that maximize impact force are the way to go. You don't need to break the shield if it doesn't negate impact Force. You just need to hit em hard enough that it harms them right through their shield.

  • $\begingroup$ About infantry : Even though you're correct, slicing and thrusting were pretty much pointless against plate armour, that didn't mean swords were useless. Half-Swording (using the sword as a "spear") and just flat out using the blade as an handle and bash with the pummel were also viable tactics, against plate armour. This helped soldiers not have to carry different weapons for different situations. Although, other than that, top-notch answer. $\endgroup$ – Oak Nov 2 '17 at 9:59
  • $\begingroup$ Although there are "unconventional" weapons that could work (greek fire, catapults, ballistas, Battering Rams, etc..) $\endgroup$ – Oak Nov 2 '17 at 10:00
  • $\begingroup$ Archery can still be useful, but more in 'sniper style'. Arrows can be used to deliver poisons, fire, messages, etc. Can be valuable depending on what kind of magic barrier we are talking about. $\endgroup$ – Olga Nov 2 '17 at 11:42
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    $\begingroup$ Archery may not exist, but slings are awesome. A sling projectile is blunt and relies on "trauma impact" much like maces/hammers do, after all. I think archery outpaced slings because archers could be more tightly packed, however in a world where packing archers is pointless, I could see squads of slings instead. $\endgroup$ – Matthieu M. Nov 2 '17 at 11:54
  • $\begingroup$ The lessened importance of archery might also lead to a higher reliance on close formations on the battlefield, at least until artillery comes into play. Shield walls and large shields in general would be less common as well - parrying shields like bucklers would probably still see use, although not on the battlefield. $\endgroup$ – Pahlavan Nov 2 '17 at 11:59

Finesse is no longer a consideration in this situation, two handed warhammers and picks and hard blows are now the best approach to any combat scenario as they will provide the greatest drain-per-strike rate. One would still wear "real armour" because more protection is more protection which is why I suggest hammers and picks, they concentrate force and are specialised for taking out armoured foes.

In light of the edit including "The barrier can be bypassed by piercing and averages around the difficulty to pierce as Steel plate armor." I would recommend the two-handed version of the Bec de Corbin, or the Lucerne Hammer with their long sharp "beaks" designed specifically to pierce full-plate steel armour.

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    $\begingroup$ "force could still be transferred" is a definitive factor that would make people to switch to the more massive weapons. $\endgroup$ – Alexander Nov 1 '17 at 16:39

Not much change really,

The medieval period wasn't known for its adaptability. As long as these shields could be beaten with brute force, methods would largely remain the same.

The tactical usage of the shields, on the other hand, would experience the most variability but that is a different question that impacts this one.

One aspect to explore though. Cavalry would potentially be impacted by this. Cavalry was a huge component of this periods warfare. Cavalry works by quickly charging enemy lines in rapid singular assaults and then fleeing before they can counter attack. Being that these shields require successive damage cavalry can effectively be halted. However you said they could be pierced like steel and in this period the lance was designed specifically for piercing mounted knights. So potentially and potentially not would this affect the usage of cavalry.


You mean every human was just born this way? Every person just has this field capable of withstanding 20 full force hits from a two-handed long sword?

The simple answer is that a lot of medieval weaponry wouldn't have been invented, and what weaponry was created would mostly be for the purpose of hunting animals not humans.

Humans would most likely have learned to use their energy shields against each other in fights rather than build weapons for that purpose, given that the field as described would have been the hardest, and most durable, thing known to humans at that time.

For example: you state that the "the armor could only become weaker than another point by a user deliberately shifting energy around themselves", which means that other areas would presumably be made stronger by doing this. The obvious question is: to what extent? Could I condense all of the power of my energy field down to a cylinder 1cm or so in diameter that projected 30-40cm out from my right hand? If so then I could presumably punch that through someone else's energy shield and their body.

Come to think of it, you describe this as a field, which means that it is not constrained by 3 dimensional physics. I could therefore theoretically project the field outward as a 2 dimensional plane that had width and length, but no thickness. That plane would be able to penetrate other fields because it would have no actual surface area on the leading edge. It also means that it would pass through the person inside the field without damaging them - again 2 dimensions, so no penetration. So what would be the use of this? Well the field wouldn't harm the person as it passed through them, but it would create a barrier that would not allow things like oxygen or blood to pass through it.

Beyond that most of the weaponry created would probably be designed for distance attacks using projectiles with a high mass since the field allows inertia to be transferred to the user.

I also expect there would have been a lot more use of fire as a weapon since the field as you describe it seems to resist penetration but otherwise still allow energy to pass through it.

  • $\begingroup$ Very interesting. Still I would have to say no on letting people have so much control over their barriers that they could use it as a weapon. It unfortunately defeats what I was going for, but could be something to explore on its own later. $\endgroup$ – Azohn Nov 2 '17 at 11:30

Let's look at the possible attack points of a person in armor. I train HEMA (medieval combat) and fight in plate armor every now and then so that's my perspective.

Gaps are non-existant with your barrier so let's skip those, but weak points are still important. A key factor to combat would be forcing your opponent to strengthen a part of the barrier and then attack a different one. Feigning, in other words. This is important in any kind of fighting, but it would be emphasised in your scenario. Combat would be primarily oriented around tricking your opponent while not being tricked yourself and then attacking the weaker parts of the barrier.

For this, a poleaxe would probably be a good weapon. You could feign a piercing attack to the chest with the shaft end and then quickly shift into an attack to the head with the other end. A properly wielded poleaxe is fast and powerful and one of the best allround weapons of the medieval period.

A strike to the head would also be a good option. A knock-out is not dependent on what damage you can do, but rather how quickly and forceful you can twist the head of your opponent. A solid straight blow in the face would hurt me, but is unlikely to knock me out. A solid hook connecting with my cheek however would twist my head enough to shake up my brain and make me go down. This all depends, naturally, on the rigidity of the barrier, but for people to be able to move around the barrier would still need to be flexible.

Another good strategy would then be grappling. By twisting the limbs you would inflict pain, the enemy would have to strengthen the barrier there to avoid injury or further pain and that's when you use a round dagger to stab them.

In general, techniques would be quick and deceptive. They would be much about manouvering the opponent into a position where they're forced to open up weak points in the barrier. Dual wielding would probably be much more common.

But blunt weapons would also be very common. A good strike might not drain the barrier, but could still inflict a lot of internal damage. Hit he belly to send a shockwave through the body that might disrupt the internal organs. Hit the head to inflict concussions. Internal bleeding might not kill as quickly, but kill it will. On that note, nets would probably be more common too. It would still entangle the foe making it possible to go in and pummel them.

I suspect that most combat techniques would be about finding and exploiting the nature of the barrier. The devil is in the details they say and that would also be true here. How quickle can someone shift the strength of the barrier? How much force is needed to pierce it and where would be the best place to do so? If I throw dust in the face of someone, will it stick to the barrier, fall off directly or go right through it? Does it work like a super strong chainmail so that smaller things can get through? Would it hold off water or other substances? What about fire? Guns would probably develop from handheld cannons to something more useable faster than it did IRL.

There are a lot of nuances here and you would do well to explore the exact nature of your barriers in order to answer this question properly.

  • $\begingroup$ How quickly can someone shift the strength of the barrier? I want to say as quickly as one can think of it, but that seems to defeat entirely the idea of feinting, which I do like. Let's say it cannot all go all at once and shifts around the person. It would probably be dependent on how much was being shifted, how far and how trained the person was, but let's generalize to half a second plus reaction time to shift it around. $\endgroup$ – Azohn Nov 2 '17 at 11:03
  • $\begingroup$ How much force is needed to pierce it and where would be the best place to do so? The barrier is as tough as steel with thickness varying based on the individual and how much they have relocated to one place. There are no weak points if energy is not being shifted around. If I throw dust in the face of someone will it stick to the barrier, fall off directly or go right through it? Good question. For now I'm going to say that it would fall off. The user could allow it through if he wanted it to, but otherwise I imagine the barrier would be so smooth that the sand would brush right off. $\endgroup$ – Azohn Nov 2 '17 at 11:11
  • $\begingroup$ Does it work like super strong chainmail? No. It works like a plate of steel. No small rings to let things through. $\endgroup$ – Azohn Nov 2 '17 at 11:13
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    $\begingroup$ Would it hold off water or other substances? What about fire? As for water and other substances I would see the answer to sand and I'm going to say that solids and liquids will be stopped by it. In theory gasses would need to be able to get in or the user would suffocate. As for fire though... I think that a burning object would be treated the same, but as I had previously stated that force transferred, I should probably have it the all energy can transfer through the shield, allowing a fire to cook or burn someone. $\endgroup$ – Azohn Nov 2 '17 at 11:18
  • $\begingroup$ Guns would probably develop from handheld cannons to something more usable faster than it did IRL. I think they may actually develop slower. Early guns only Dented armor. Combine that with the high reload time, low accuracy and cost, the performance of early firearms might be so bad that they are forsaken for a long time. That said more advance firearms would mostly invalidate the advantages of having such a barrier in the first place. $\endgroup$ – Azohn Nov 2 '17 at 11:24

Many interpretations of "magic" suggest that it is susceptible to raw, unhardened iron. If such is true in your world, the advent of steel would actually hurt warrior effectiveness and safety. Such a world might not develop metal hardened techniques until much later.

  • $\begingroup$ I always felt that for the same reason iron was effective against magic so too should steel be. But that's a rabbit hole of a subjective conversation $\endgroup$ – anon Nov 1 '17 at 16:52
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    $\begingroup$ @anon, Funny. I always accepted that it was an issue of purity, not chemistry. The cold iron was a pure creation where as steel is corrupted with carbon for greater strength. That magic worked the opposite of reality, succumbing to soft iron yet rebuking hard steel... that just seemed somehow right to me. $\endgroup$ – Henry Taylor Nov 1 '17 at 16:58
  • $\begingroup$ see I took it like this, magic came from nature, because iron was stolen from nature and crafted/corrupted by man so that it was no longer part of the natural life cycle (life and death) that is why it had anti magic properties. Different from wood because wood still rots. From this perspective there's no difference between steel and iron $\endgroup$ – anon Nov 1 '17 at 17:34
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    $\begingroup$ No comment on whether or not steel and cold iron should be the same for overcoming magic, but I find myself torn by this answer. On the one hand fae being weak to iron is a thing and a fairly clever thing with its own rabbit whole of altered development, but on the other it sort of defeats the purpose in my mind if the barrier can be so easily subverted. $\endgroup$ – Azohn Nov 1 '17 at 17:53
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    $\begingroup$ Mercedes Lackey handles your "the barrier can be so easily subverted" issue by setting her Serrated Edge series of books in our modern age, when aluminum and high-carbon steel have replaced most works of raw iron. Your targeted medieval period doesn't enjoy that luxury but perhaps a shortage of easily mine-able metals could accomplish the same thing. Anne McCaffery portrays a really good iron-poor castles and knights kind of story in the early books of her Dragon Riders series. $\endgroup$ – Henry Taylor Nov 1 '17 at 19:40

Sneak attacks will be even more popular. Much less fighting in big numbers. Maybe sophisticated traps (bear traps used as mines?). More usage of fire and poison.

You really want to deliver your blow out of blue since it means it will land.

  • $\begingroup$ Sneak attacks are popular in any time period, the hindering factors remain the same: where is the enemy and how do I get to him undetected. I think you mean assassination $\endgroup$ – anon Nov 1 '17 at 16:54
  • $\begingroup$ @anon but if you get detected, you have more chances to flee by projecting a barrier. $\endgroup$ – alamar Nov 2 '17 at 9:05

Troop rotation

People have a lot more opportunity to retreat without harm. A reasonable rotation after taking a couple hits and swinging a heavy weapon for a few minutes to give time for the magic to restore or at least to take advantage of all your troops' magic becomes even more important. Longer encounters also mean sustainable fighting is relatively more important than ferocity.


A traditional problem with conscripts is they die in droves learning how to fight. With magic armor this is much less true; they have 19 hits to learn from and maybe more if the magic recharges.

Shoving matches

If you have a big mob of poorly trained (and probably armed) people who are difficult to hurt pushing and trampling seems like the goto plan. Like a shield wall without necessarily even needing the shields.

  • $\begingroup$ Once engaged, rotating troops between front and back is an extremely difficult task even for a professional and well organized force like Roman legion. Having a spare reserve would be a different scenario. $\endgroup$ – Alexander Nov 1 '17 at 19:15
  • $\begingroup$ @Alexander A lot of why it's difficult is because someone letting their guard slip during transition is a problem in our world. This is much less true with this magic. If everyone in the old and new frontline each take a couple hits while switching that's a net win with the magic armor and suicide for us. $\endgroup$ – user25818 Nov 1 '17 at 19:26

This sounds very like the shields from Dune. The characteristic feature of these shields is that they block all fast objects whilst letting slower objects through.

Long-range weaponry is therefore minimal. Hand-to-hand combat is predominant, and fighters are trained to move slowly in attack to get through the opponent's shield. Since slow movement with a longer weapon such as a sword would be easily countered, hand-to-hand combat tends to use knives. This especially focusses on dual knives, because as Paul Atreides says, "Attack has the sole purpose of tricking the opponent into a misstep, setting him up for the attack sinister".

  • $\begingroup$ I thought about this and should probably specify, that I had no intention of the barrier discerning between fast and slow objects. It is however, a valid and interesting way of doing things. $\endgroup$ – Azohn Nov 2 '17 at 11:35

Having such an efficient armor, that can not be easily surpassed by anything man-made and practical to wear with the technology available, people would never attempted to create any concept of personal armor, shields and the like.

This would give the soldiers far greater mobility in general and thus favor tactic that where common before good armor developed.

To fight such highly mobile and well defended targets they would develop weapons with the capacity to store energy, to quickly piece the enemy´s shield before he can retreat and recover. Crossbows would become the no 1 weapon on the battlefield, and maybe even some sort of spring-loaded spears or daggers.

With the ability to just recover your armor, tactics would generally revolve around being able to retreat before you are drained and denying your foe the same opportunity.

Guerrilla-tactics and ambushes would be most effective to quickly take down shields and make the kill blows. Also fortifications would be build that way that the defendant could rotate his front line and decide where an when to fight, so could equalize the number of enemies to be irrelevant.


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