Partly inspired by this thread although I’ve been wanting to do this for awhile.
Take a World War II army – it has an extremely large number of soldiers relative to any other period of time – millions, thanks to modern medicine, agriculture, and transportation networks.
Now, take away their vehicles and explosives. Let them keep their bayonets, and rear-echelon vehicles and trains, and radios, etc. I’m torn on airborne reconnaissance.
Which historical armies could beat them? I think Napoleonic era armies, while outnumbered 6 to 1 or more, would stand a chance because of their cavalry and artillery. WW2 armies still had some cavalry but you couldn’t really charge well with a bayonet so they’d be mobile infantry. And muskets wouldn’t be that much of an advantage when outnumbered because the WW2 army could simply charge once in musket range.
Civil War armies would win because of the rifle.
I think the Mongols would win because of horse archers. Any other army that relied on horse archers was so small that they’d run out of ammo before the modern army ran out of soldiers.
Any non-gunpowder, non-horse archer army would be so small that it would be outnumbered 10 to 1 or even higher, against relatively high morale troops who would not break and run when confronted by cavalry, and would simply beat foot soldiers through sheer mass of numbers.
Depends on a few variables. If we are talking say equal numbers of general issue soldiers my bet would be on almost any pre-gun force taking out a weaponless WW II force. Especially if we put the conflict in the terrain of the historical unit. Now you want to talk equal numbers of say say WW II Rangers or SAS – that becomes a little more of a toss-up.
It would definitely not be equal numbers: the modern army would have more because their population is higher. And the terrain of the historical unit might be moot because the modern army could still use modern communication to help choose the battlefield.
I think that, given a modicum of training and some ancient weaponry other than just bayonets, that the modern army would be around a match for the ancient one, man for man, because the ancient army would still have more experience and training but the modern one would still have the logistics and communications advantages, and the size advantage of modern nutrition would partly but not entirely ameliorate any physical toughness of the ancient soldier.
If you “Dies the Fire” a modern army, you’re left with a bunch of guys armed with third-rate pikes - and no training or experience in pike warfare. I think pretty much any historical army would be able to beat them. An army with rifles, muskets, or even bows would have the range advantage on them. And even a non-ranged army like a Greek phalanx would have the advantage of experience in fighting hand-to-hand.
If you leave them their rear-echelon vehicles, those will end up being their best weapons. As long as they are fighting on even ground, a ramming car will wreck havoc on pre-gunpowder enemies. All that gasoline can be used to make molotov cocktails too which would be handy against big infantry formations.
I had meant rear-echelon vehicles to not be used in combat but that might be unrealistic. Perhaps only trains and planes? (Yeah, planes could drop bricks!)
Against any army using gunpowder, I’d expect the WWII army to win, by virtue of special forces equipped with communications technology and training superior to ancient training. An attack on an armory to equip some of the WWII troops could change the tide.
There’s also the tremendous strategic advantage in knowing your enemy: most historical armies have relied on strategies and tactics that are taught in 20th-century military colleges. Someone in the WWII army will know what strategies any particular army relied on. The reverse won’t be true.
They might be advised to leave some special forces troops behind the scenes to harry the opposition, while everyone else engages in a scorched-earth retreat: the logistical superiority granted by modern vehicles will mean they can travel, and feed their own forces, much more effectively than their opposition. Meanwhile, the backline troops will train as quickly as possible in whatever weapons are available to them–whether it’s hastily-fashioned bows, spears, bayonets, or the ballista that the engineers are building.
Can they dig trenches? What would trenches be like vs. cavalry?
Due to population, logistics, and health I would think the WWII army would win without any particular brilliance. Yes the first wave of past soldiers might be successful at killing a lot but they would eventually fall due to attrition and the WWII guys would acquire the fallen’s weapons and the tide would turn. The first guys into normedy didn’t mostly survive but they overwhelmed the Germans by shear numbers. Each of the WWII guys would on average be much healthier than soldiers of times gone past and as they acquired weaponry they would win. Sort of how Russia sent more troops against the Germans than they had guns and expected the weaponless to either grab the gun of the fallen or of the enemy soldiers.
Do they get to keep their medicine and logistics (i.e. they won’t starve or anything, right?)? If so, then I’m going to go with the modern army. Basically, they wouldn’t need to even fight any battles…just march around and let the other guys die in droves from disease and hunger. If you are leaving them vehicles and trains and such, they can move much more rapidly.
Are they allowed to improvise weapons? Or use weapons from their enemies? Can they capture weapons or buy them in trade? Do they still have an industrial base behind them, supporting them with non-war materials and logistics support? If all of these then I think the modern or I guess more modern (WWII) era army would win against pretty much any Civil War or earlier army with all their modern weapons gone. They would, to paraphrase from The Last Dragon (which I watched this weekend :p) simply have to master the art of fighting without knowing how to fight using the weapons of the day but instead using their own logistics, superior mobility and speed and medicine to allow nature to kill off their enemies or weaken them until they could beat them with rocks.
Trains without tracks would be pointless. Tracks in a primitive land become iron mines.
An army of modern soldiers with only Bayonets and radios can still be a formidable force if their leaders are intelligent. They can strike a thousand places at once and every group knows where the enemy is. I would stage raids on food sources and weapons depots, seeking better armament along with disruption of the enemy’s supply train. You could quite literally bleed a Roman Legion to death by a thousand cuts (small ambushes and supply raids) while avoiding any large engagements.
While I would expect that my modern force would be susceptible to ancient diseases and the wide exposure to parasites, I would also expect my hygiene practices to keep most of my men going while the other army bogs down and loses people to easily preventable diseases.
In any event, if my army survives the first month, I’m entrenched in fortified positions or on the move, and well armed with local weapons I took from any opposition as well as ones we made in local smithies.
Take a few tanks and run over the soldiers and their horses together. They’ll run away pretty quickly and announce you the winner.
The bayonets, on their own, would be pretty useless except against soldiers with muskets, since they’d be fighting with bayonets as well. Anytime before that and the soldiers would have a spear and, importantly, a shield. Your bayonet versus a guy with a spear and a shield, and you’ll be cleaned up pretty quickly.
If they just hide out somewhere for a while, rather than going on a rampage for land, any chemistry and medical majors could probably figure out how to start up a production line to create cannons and some nasty chemical warfare devices. Just recreating the landmine would probably be a significant advantage against many armies.