+1 upvote because thanks for clearing the misconception in other answer since i see it a lot and i myself tired to attempt to clear it, people in the past is not dumb. honestly though this soldier can do well as crossbowman just like genoese crossbowman they do well in crusade after all rather than melee combatant, although OP disqualified any invention, if they has pavise shield i can see they use it as mobile cover.

The only answer here even vaguely accurate. Good job!

Completely agree. They will turn up, get a stomach ache from the bad food and dodgy water. Spend a few days having fever from food poisoning. All the locals will be like "these people are pathetic". Also, all this stuff about discipline in other peoples answers, WHY would this company of randomly time-shifted people have any discipline? Maybe a modern US Marine is disciplined, they are loyal to the ideals of the USA and its government, they will risk their lives for its people. Send them back in time 1,000 years and what the hell do they owe the crusaders? Might as well desert day 1.

I think most of your observations make sense but what about strategy and knowledge? We realized, not all that long ago, that lining up in a field and firing arrows or guns at each other was pretty dumb. Wouldn't using hit and run and guerrilla tactics completely change the way war was waged? Would just the knowledge of modern technology be useful for waging war? When did we discover hot air could lift things? Maybe the present day soldiers wouldn't know how to build a hot air balloon but just giving their inventors the idea would allow them to use the resources of their day to make one.

@TracyCramer massed charges/massed fire tactics were completely viable until the technology advanced to have a rate of fire that became too fast and too deadly. With bows and crossbows the rate of fire wasn't that great and it was entirely possible for arrows/bolts to be deflected by armor with no effect making it so that to achieve any reliable damage you needed mass fire to try to hit a weak point. Pre industrial revolution the production capabilities of nations were already so low I doubt you could easily get the resources and man power to introduce a new technology like a hot air balloon

About all the knowledge that you call useless, I want to add that it would be useful knowledge if they could apply it on a big scale. I'm sure there are SOME aspects of logistics that can be improved, you could carry boilers and some fuel to at least clean wounds with boiled water, there might be some encryption knowledge that's useful to decrypt some messages, etc. As soldiers they would be useless, but as knowledgeable strangers, wise foreigners, wizards from Arda, they might actually make a difference. If only someone would listen to them instead of just giving them a sword...

I think this answer is overly pessimistic. Many of the points are debatable and/or could go either way, most underestimate the ability of humans to adapt. (E.g. sure they would need more food, but then they's also be bigger and stronger than most medieval soldiers so their generals would give them more food to keep them in fighting condition).

This message has just gotten up a head of steam to criticize other answers with great haste, in a wall-of-opinion, with not a thought toward supporting any comment. I thought [citation needed] a dozen times reading this, because so many things are so wrong. In fact, it's not even an answer, just a series of drive-by comments, quantity over quality. Not really our format here.

I downvoted this answer, because while overall it's sound, the statements about logistics are simply incorrect. Maurice of Nassau, Cromwell, and Gustavus Adolphus did vastly better with logistics than the Crusader armies - as did the Romans, for that matter - without having modern resources at their disposal. It's not simply a matter of industrial societies having more stuff. It's a matter of conceiving a system of logistics in the first place.

@tbrookside What do Cromwell, Gustavus Adolphus, Maurice of Nassau, the Romans and the modern US Army have in common? Some powerful, rich states and a decent navy at their disposal. If Cromwell or Nassau had been disembarked in Lebannon, then the fleet had been dismissed they would have had the same problems the Crussaders had. I never denied that logistics is vital. I only stated that wishing logistics is not useful. Most answers here are overly positive verging on naive. The path from theory to realization is always an order of magnitude greater that initially thought.

@tbrookside also, there's a difference between having a supply train that takes on average years through hostile countries (crusader scenario) and one that takes months through own/allied one (Cromwell, Romans, Gustaf 2nd Adolf). The Crusaders are much more comparable situation of Carolus Rex in the 1708-1721 part of the Great Northern War, when the swedish army was pretty much cut off from supply trains. In some ways, the Crusaders are even in a better situation.

@toolforger What point it is being bigger and stronger if they can't use a sword or a bow? They are worse fighters and, on top of that, they eat a lot. Any wise commander would put them on the first line as human shields to get rid of them at the first opportunity. Whenever the army has been deployed as riot police they have underperformed badly. You just can't handle them shields and batons and expect them to perform as well as a thorougly trained unit. That would be the same, but way more deadly (for them).

As an Army Veteran, I'm going to say that a lot of this Answer isn't correct. In Basic, we were taught how to do many things without modern technology. An infantry unit would be taught more of these techniques, including how to avoid food poisoning and how to live off meager food sources. Infantry is also taught how to infiltrate a campsite, become "invisible", and many other things that would be invaluable to the Middle/Dark Ages. A Medic would also be invaluable, due to removing the bad practices that made things worse back then. And a sniper would become an Officer quickly, for tactics/etc.

"The Man Who Came Early" by Paul Anderson is an entertaining reading on the subject, although limited to just one time traveler.

@computercarguy Bollocks. That's like saying that a time-traveller from the 24th century will outperform you in things like driving a car without IA or using a phone without voice-commands because they have a 101 course on primitive technology. What you call "doing things without modern technology" they called just "living" and they were vastly more apt than you at doing it. Day by day. Modern abilities on camouflage and infiltration were useless back then because in a world without electricity you couldn't see your one hands for inches in front of your eyes. Night was really dark then.

@computercarguy Also, infiltration can be useful in a time where a platoon with automatic assault rifles and some kilos of C4 can unleash the Armaggedon. Without pictures of the enemy campsite took by spy satellites or drones, without night-vission glasses and armed with short swords (and without heavy armour, because it's cumbersome) your infiltration team can't do too much damage and it's hopelessly disavantaged in a night darker than chinese ink through a labyrinthic enemy campsite they don't know fuck about.

@Rekesoft, you assume that everyone in the military always has night vision 100%. I never used it, yet we did night maneuvers frequently, even in my Reserve unit. You also assume too much about the use of technology in the military. It gets used frequently, but even today they get trained what to do when it fails. The training is more than a "101 course", especially when you're talking special forces or marines. "Modern abilities" about camo is funny. A ghillie suit is a net with strips of dyed cloth and local plant tied on and first used in 1916.

And a surgical strike while the enemies are asleep, with minimal guards and fires everywhere could be done with minimal recon on a nearby hill. It's considerably outside of the "normal" rules of war at the time. They might have done raids, but not as quiet and stealthily as with today's methods. You might also be surprised to know black powder was used in the Cruisades. prezi.com/xar5t4reohat/… I'd also expect a racecar driver from the 24th century to out drive me.

@computercarguy "And a surgical strike [...] with minimal recon on a nearby hill". The camp is on that hill. In modern warfare you don't want to be there, cause it's easily visible and hence an easy target for artillery. In medieval warfare, fighting downhill means your arrows had more range and melee was easier. So ironically, that comment supports the opposite of what you were trying to argue: You're used to modern warfare doctrines which work against you here.

@R.Schmitz, I think you missed my point. You do the recon of your enemy from a nearby hill to get the basic layout of the camp, then you go in at night to destroy them. They won't have the ability to get arrows launched, since you'll already be in close quarters. And you use modern stealth tactics to take out the guards. Medieval rules of war required you to announce your presence. Medieval machismo required a war cry before attacking. Modern warfare means stfu, get in and get out quietly, and do as much damage as possible before they know they were hit.

@computercarguy I think I still miss your point... are you assuming you have binoculars? Or are you assuming you're fighting an incredibly stupid general, who put his camp on a hill which is right next to a higher hill from which his camp could be observed easily? Admittedly, that second option is at least not impossible, but not something to reliably build a strategy upon...

@R.Schmitz, you don't need a taller hill to be able to see a significant amount of a camp, since that target camp isn't going to fit on the very top of the hill. It's not like a plateau where you can't see any of it unless you're taller than it. And you can see significant enough detail with your eyes, even at a distance to get a general layout of the camp to do "dirty deeds". The general will likely be in a larger tent, you can see patrol patterns, paths between tents, and more. If you need a better view, climb a tree. And there are ways to make your eyesight better without a telescope.

Also, unless the soldiers arrived naked, they likely brought a set of binoculars.

@computercarguy "Medieval machismo required a war cry before attacking" - Just... no. Add "underestimating the enemy through over-confidence" to the list why modern soldiers would be worse. The concept of stealth was not invented alongside firearms. The ancient Romans already lost battles that way (e.g. Lake Trasimene or Teutoburg forest). And no, there wasn't any Hollywood-ish notion of medieval chivalry that put a stop to these tactics; at Dupplin Moor, the sneaky guys got a little off target because of fog, but they won the battle pretty much the way you describe it.

And things like camo face-paint and ghillie suits get you into firing range unseen, but not into melee range - let alone into the camp. And we're talking about a camp for tens of thousands of people here. In modern warfare, gathering even just a thousand people in one place like that on the front lines, would just be a target-rich environment for the enemy's artillery. Can you see why I would bet money against somebody getting close to the general, probably sitting in the center of this with his personal elite guard?

@R.Schmitz, I'm not talking about ambushes or traps, I'm talking about getting into camp during the night to kill or capture the enemy leaders without the rest of the army waking up. And yes, ghillie suits and camo will get you that far, since ye olde enemy isn't looking for that kind of attack. Heck, you could probably breach the perimeter just by pretending to be one of them and coming back from taking a leak at 2 am. And modern guerrilla warfare is very different from pitching a 10k troop camp. We simply have +1500 years more experience to work from.

@computercarguy Way before the US Forces took the badge of being the best specialists on night attacks, this merit was of the spanish Tercios. In their 80 years long struggle in the Netherlands they were reknowned, among other things, for their dreaded "encamisadas", surprise night attacks on enemy camps. They well called "encamisadas" because the Tercios' soldiers would wear a white shirt (camisa, in spanish) to tell them other apart among the chaos. Wearing a white shirt as a ghillie suit? Yes, because, in a world without electricity, the major problem was seeing, not avoiding being seen.

@computercarguy I'm afraid that most of what you (think you) know about ancient warfare comes through Hollywood movies. No, camo paint and gillie suits doesn't give you much advantage in a world where, in a nigth without moon, you could not see your own hand three inches away from your nose. And don't expect recognition to offer much help, either. Usually soldiers put their tents wherever they could, so the only disposition of the enemy camp you are going to get is "like the Woodstock 69's camping area".

@computercarguy "Heck, you could probably breach the perimeter just by pretending to be one of them and coming back from taking a leak at 2 am" - YMMV, but usually a big part in keeping a spear wall standing was that your childhood friends from the same village were standing next to you and running meant you'll leave them to die in a broken formation. "ye olde enemy isn't looking for that kind of attack." - And thus, our modern soldier dies much quicker than a contemporary soldier, by underestimating the enemy.

@R.Schmitz, most temporary camps aren't going to have a "spear wall" built, especially for anything less than a week campsite. And I was saying that the medieval soldiers wouldn't be looking for someone in a ghillie suit, so would walk right past someone wearing it, and likely wouldn't notice a bush that moved during the night. Also, I was talking about a surgical strike, where you kill key people and leave everyone else to wonder what happened when they woke up leaderless. I'm definitely not talking about a night melee. Also, a camp is likely to have fires, so definitely more light.

@computercarguy "Spear wall" as in people standing in a row, holding the pointy ends of spears towards the enemy. The thing that developed from the Greek phalanx, which relies a lot on the line remaining a line. The point being, the soldiers in a unit (camping together) usually literally grew up together. Even if you somehow manage to get your hands on attire from that specific village, good luck pretending to be a guy they've known for 20 years when "coming back from taking a leak at 2 am". The rest still sounds more like Rambo movies than reality.

@R.Schmitz, so you are going to have that spear wall standing at 2am?Or are you implying that an army of 10k people all know each other? Psychologists generally agree that an average person knows 150 by name. After that, they are strangers, with maybe face recognition. Even if they grew up in the same village, which in an army of over 5k wouldn't be likely, they could easily have lived in different districts and never interacted. My HS graduating class had just over 400 people, and I didn't know half of them, let alone ever saw them before they walked the stage.

@computercarguy It's becoming more and more disassociated from the real world. No, they will not stand in formation at 2am. The point you now missed for the second time is that the army consists of small "islands" that know each other very well. You dress as one of that group, they will immediately know that you're a spy. No Geneva Convention for you. You might have luck that the guard is not from that group. A grunt might think this a good idea, but an officer won't base their tactics on nothing more but luck.

Guess what, your next comment will try and think around this while having a "they were so inferior" mindset again. This has just become too tedious. You can't just work with one detail here. If you want to understand medieval tactics, you'll also have to have a good grasp of the strategies, which in turn are adapted to the historical context they spring from. If you want to come up with something that makes sense, you'll just have to pour hours into learning about it. Otherwise you'll keep coming up with suicide missions based on Hollywood movies.

@R.Schmitz, it's become pretty obvious to me that you have a very specific idea of what "can never happen" and this falls well into it. The "islands" you talk about were typically well mixed inside an army. And even if they managed to stay together, someone from another "island" could easily walk through another "island" or enter the camp in another "island" other than their own. You trying to poke tiny little holes in an idea that you obviously don't understand at all, then complain when I have the obvious answer you couldn't come up with on your own. This argument is not my fault.

Thinking on your feet and making snap judgement calls is the core of the modern military. Simply charging ahead and not changing tactic was very prevalent in older militaries. There's a reason "The Charge of the Light Brigade" resonates with military people, as well as the fact that the current US military allows leeway with even squad leaders to accomplish missions, rather than being required to follow the micromanagement of generals who refuse feedback from the lowest ranks. Discrediting any kind of change or clarification is exactly why an ancient military will fall to a modern threat.

@computercarguy Well, I'm done arguing that people in the past can be not stupid. However, you're clearly interested in military history, so here's a couple interesting tidbits that you seem to not know about yet: 1) There's a pretty good chance that soldiers from 2 British medieval villages won't understand each others dialects. 2) When Hitler took soldiers from all over Germany to create the Division Grossdeutschland, it provided a sort of unification propaganda bonus for Germany. In WWI, German regiments were still mostly sourced from one or two provinces. That's how relatively novel the...

idea of mixing soldiers in units is. 3) The Charge of the Light Brigade was a communication issue which wouldn't have been solved by anybody wearing ghillie suits or otherwise being sneaky. 4) In the Battle of Cynoscephalae, a Roman officer pulled off a detachment of soldiers from one ongoing fight in order to attack a phalanx in the rear elsewhere. That officer-level decision making - as early as somewhere around 300 BC - was a vital part of the Roman victory. Quite the historically important battle, too, as it cemented the superiority of Roman manipular tactics over the Greek phalanx.

@R.Schmitz, and obviously you still don't understand anything I said, unfortunately. Also, officers are high ranking people who are supposed to make decisions. In the modern military, squad leaders (E-4 or E-5) are allowed to make some decisions. And obviously you have somehow taken my examples as examples where my suggestions wouldn't work, when instead I offered them as reasons why ancient solders wouldn't have a chance against the stealth tactics and diverse decision making of the modern military. You evidently don't know how flexible, efficient, and effective modern militaries are.