Most Effective Ancient Weapons System if Combined Arms isn't an option

Question

Short Version: If everyone in my army is going to be armed the same way, what is the most effective weapons system that isn't a horse archer? It is understood that this is still not as good as combined arms armies with more specialization, but for story reasons please just go with it.

Long Version: To my knowledge, and please correct me if I am wrong, the Mongol Golden Horde was able to conquer a fair bit of Asia with an army made up almost entirely of horse archers (as well as some siege weaponry at times). Their skill, as well as their ability to attack from range and outflank enemies with great speed, made them arguably the greatest fighting unit of the Ancient world. Again to my knowledge, they didn't have any major weaknesses because anyone who was armored enough to avoid dying by arrow fire had no chance of catching them, and if chased they could retreat into the Steppe until your supplies ran out. This has me wondering what the greatest weapons system in an ancient world setting could be, outside of horse archers.

In my story there is a nation that arms 95% of their military in the same way for reasons. While this is certainly not ideal, it is their only option. I have considered the entire army just being excellent archers, but I'm not sure that's the best solution. I have also considered Hoplites, but again not sure whether that is the best course of action. The solution can't be horse archers, if only because I want it to be slightly more exotic than the familiar raider stereotype. The uses for this military will be primarily defensive, fighting both in open pitched battle and defending walled cities, with occasional requirements for offensive engagements. They will be facing multiple combined arms armies similar to troops from the Ancient Era. Flexibility and being at least average at most things is therefore a must. With again the understanding that this army on a practical level is at a massive disadvantage, how should I arm them to give them the most realistic chance at defending their nation with only one troop type for 95% of their army?

Edit: Nzaman pointed out that the environment is crucial here. Therefore, this is an area about the size of Ireland, with mountains surrounding it. Other than the mountains and foothills, there is a very large almost impassable swamp, and some gentle hills giving way to plains.

Bonus points if the answer includes what the 5% "Special Forces" units should be armed with to act in support.

Addendum: Possibly unnecessary info, but the world in question has magic to some degree. I would prefer the military strategy mostly avoid using this, but if a little magic can aid in an interesting answer then go for it.

Answer 1

Macedonian Phalanx

My First thought was either Samurai (of the Yari and katana variety) or Legionary (gladius/scutum/pila) but both those exemplars may violate the "single system" requirement. So if you only get one weapon, a Sarissa (pike) is the way to go!

Pros: 1:Your style of warfare is defensive*, and the country is mountainous giving way to open country/swamp. This should allow you to anchor one or perhaps both ends of your battleline on terrain features which would prevent the enemy from hitting your phalanx in the flank/rear. As phalanx aren't maneuverable anyway, these sorts of narrow battlefields are perfect for them!

2: A pike phalanx is one of the most effective fighting formations in history, and it shows. Yari ashigaru came to dominate Japanese warfare in the age of samurai, the various ancient Mediterranean armies, the "Pike and shot" era pike blocks... if you're on foot and need to kill the enemy with a weapon you can hold in your hand, the pike is the way to do it! It keeps the enemy at a distance, while also forcing each foe to essentially fight multiple enemies (as the back ranks can stab past the front one).

3: Deep pike phalanx, with the back ranks slanting their pikes forward over the rear ranks, are actually pretty well protected from arrow fire until the range is near point-blank. The arrows largely plink of the forest of pike shafts/tips above your troops, robbing them of most of their penetrative power. Your biggest problem (as the greeks found out) would be javlins, which are themselves heavy enough to knock aside a pike and still kill the man they hit. But as an offensive weapon 20ft pike is > guy with spear/sword and shield (generally anyway). This is important as you don't have anything to suppress enemy ranged weapons short of running over and stabbing them.

4: Pikes are generally effective against infantry, and essentially invincible to shock cavalry to their front. Contrary to popular fiction, even a well-trained charger will NOT run itself onto spears just because its rider wants it to. What's more, a rider would NOT want his mount to run itself onto spears! So if your pike phalanx is disciplined what'll happen is the cavalry will charge, stop, and mill about in front of the unbroken wall of pikes for your men to stab to death. Add that to being moderately well protected against arrow fire and you've got about as well-rounded a single-system formation as you can expect in the pre-gunpowder era.

Cons: 1:Hard to control. Once a phalanx gets going in a direction it's hard to change that direction. Which is why positioning is key.

2: Poor pursuit/coverage. This will be true of any mono-heavy-infantry army, but perhaps even moreso with a phalanx. Chasing a running man whilst in armor holding a 20ft spear is... difficult. And if your phalanx disintegrates its extremely hard to cover the retreat. So you'll both have a very hard time turning a victory into a route/massacre (important to make sure the battle is as decisive as possible) and be more likely to suffer a route/massacre if you're beaten.

Given the above, your 5% "special forces" unit should be light cavalry, preferably with bows/javelins and lances. These troops would provide the quick pursuit factor required to turn a win into a massacre, as well as give your beaten forces a screen to retreat behind should the battle go against you. (and lets face it, it's likely to in the face of a solid combined-arms force) They'd also be an okay screen to keep enemy skirmishers off you, but since you'd only have a few of them relative to your overall force it'd probably be wiser to keep them back for a more decisive role.

*By "Defensive" I mean the strategic defensive. Once the army is on the field a phalanx does not (and certainly should not) just stand around as a defensive formation. It needs to press forward and grind down the enemy. Traditionally this grinding was augmented with a cavalry charge into the enemies flanks, but you won't really have that option. Such is the perils of an army equipped identically! Still, the push-of-pike should be enough to get the job done on its own, your losses will just be higher than they otherwise would be.

Answer 2

Spears

A spear is relatively simple to make, and the wielder can use it as a melee or ranged weapon. They can be awkward in close spaces, but if this is the society's only weapon, then they probably serve as staves, too. Or everyone could carry a second, shorter "backup" spear, similar to how riflemen also carry a pistol sidearm.

Spears and staves may also have some room for customization on the individual level. You could wrap some hammered metal around yours for strength, or mark it with paint and dyes for ceremonial, formal, or personal reasons.

Spears are also practical for hunting wild game and fishing, although it is definitely "hard mode."

Spears can be mass-produced even in the ancient world without modern tech or processes. And if this is their only weapon, perhaps they've bothered cultivating special materials. For example, bamboo is a tough, fast-growing wood grass. Perhaps this society makes their spears out of some bamboo analog that they've domesticated and selected for growth speed, hardness, weight, lack of knots, etc. They probably have "spear fields" where the uncut shafts of not-yet-spears erupt from the ground like fur on a wolf's back.

Answer 3

Biological weapons

The invaders rejoice to see that they attack a country of pacifistic believers. The natives have no swords, and pose no resistance: they do as they are told and patiently await divine mercy. They do occasionally tell the invaders that God will convince them to go away.

Yet, somehow, the conquerors have bad luck all the time they oppress the faithful. Buboes, boils, diarrhea, croup, black water fever, the sleeping sickness ... their torments seem endless. The locals offer to teach them how to pray, yet empty words seem to do the unrepentant barbarian horde no good at all. Sometimes when surprised in raids the locals can be seen to engage in peculiar rituals: raising flies and mosquitoes in cages, making bitter-tasting ritual cakes out of mold, jabbing infants with spikes and little threads soaked in once-heated putrid matter.

Eventually the invaders may get the sense that the locals are using witchcraft on them. A soldier out pillaging, or otherwise entertaining himself, finds himself held down, knocked out, kept for a month in a cage for sick ferrets until he gets sick himself, then they let him go. (On recollection, this was right before the Great Plague started...) Nonetheless, killing the locals doesn't seem to help with the outbreak.

Many ancient wars were halted by plague. Who really knows how that came to happen?

Answer 4

They are all engineers.

This is taking something real and making it more awesome. Your soldiers engineer wherever they go. Defending fixed structures is their favorite, and so when they go out they engineer the battle field even as the battle is going. They build ad hoc engines and towers. They dig in. They creatively employ fire, water, landscape and animals at hand. They have a few giant ape men with them, who do the heavy lifting but who are noncombatants.

Military engineers are real and really important from ancient times until now. They get less glory and screentime than the buff dudes with the loincloths and spears. But for a fiction, riffing on this aspect of real military operations would be sweet and also provide more to write about than "Dude2 got clobberized, and with his teeth he bit the earth". Which is fine the first few times but it gets a little stale.

Answer 5

Any competently led combined army would defeat single type army - you would do so by exploiting inherent weaknesses of single type, as any have it.

But combined arms component do not need to be large - you can have 80-85% of preferred type and 15-20% of others.

For a broken terrain you describe, I would actually suggest italic and Roman style - shock infantry with big shields, javelins and swords. This would then have, say 10% cavalry and 10% missile troops as support. The problem with such army is the need for very high morale and discipline as most troops need to be aggressive and that is not natural and has to be trained into people.

A long answer:
The only military system that had close to the ratio you desire was the classical Greece, where armies consisted to a large degree of hoplites. But that was due to specific nature of society in the city states - population was divided into egalitarian citizens and the rest who were either foreigners or too poor buy arms (many of them were slaves). Plus horses were super expensive as they had to be imported from outside. As result most served as shieldwall spearmen, but all hoplite armies had some cavalry and missile troops. In fact this phase was rather short, about 150(?) years. As the time progressed, light forces became more important, in later stages of Peloponesian Wars well trained light troops shown the ability to defeat the best hoplites (Spartans).

Another similar system were vikings and English armies fighting them (fe. army of Harold II at Hastings). This was because Vikings going on small scale raids carried no horses and only a few missile troops.

In other cases you would always have combined arms to a degree.
For example:
Ancient Roman triple acies was combination of missile troops (velites), shock troops with missiles (hastati and principes) and defensive shieldwall spearmen (triarii). They always had cavalry (300 per roman legion (7%), more in allied legions). Later, in early empire period roman legions were more uniform and kept only shock component, but this was always supplemented by missile and cavalry that were either allied or mercenary.

In fact, even steppe armies used combined arms - both Partians (who defeated Romans at Carrahe) and Mongols had small forces of heavy (shock) cavalry. Their role was to defeat any enemy cavalry pursuit and force their missile troops to hide behind infantry. They would also dismount and fight on foot if it was needed.
They were not so invincible, in fact. They could only go where a massive plains were and could only make small scale raids outside such areas as they needed massive amounts of pasture lands for horses. That's why Mongols never reached western Europe, that's why Partians never managed to defeat and push Romans from Syria or Asia Minor.
BDW, the land you describe would be unsuitable for Mongol style army.

Answer 6

My answer would be largely based off classical Greek warfare.

I would suggest majority of your army be skirmishers. While in a 1 on 1 with any almost other type of soldier they would would probably lose, one of their large advantages is in quantity as they are far cheaper to equip. Other than mounted units, they would have the most maneuverability, and able to quickly surround heavier enemies. Their mobility made skirmishers also valuable for reconnaissance, especially in wooded or urban areas. Skirmishers also benefited from being able to execute both shock tactics (via human wave attacks with short swords) and fire tactics (through volleys of arrows, sling stones, or javelins). It is key they have some sort of small melee weapon (like a dagger or short sword) and ranged weapon so they can employ the most versatility.

Skirmishers, were often considered to have very low status as their hit and run tactics went against the Greek ideal of heroism. While they were mainly ignored by most Greek writers, there were usually many more skirmishers than other types of units. For example, Herodotus, in his account of the Battle of Plataea of 479 BC, mentioned that the Spartan Army fielded 35,000 lightly-armed helots to 5,000 hoplites, but there is no mention of them in his account of the fighting.

Nevertheless, skirmishers then chalked up significant victories, such as the Athenian defeat at the hands of the Aetolian javelin men in 426 BC and, during the same war, the Athenian victory at the Battle of Sphacteria. (The dichotomy of elite hopilites against enslaved helots maybe useful for narative)

Later skirmisher infantry gained more respect, as their usefulness was more widely recognised and as the ancient bias against them waned. Peltasts, light javelin infantry, played a vital role in the Peloponnesian War, and well-equipped skirmisher troops such as thureophoroi and thorakites would be developed to provide a strong mobile force for the Greek and the Macedonian armies.

A key part of their use is the skirmisher is their compliment of a much smaller number of heavy infantry which can be used for them to hide behind.

Speaking on the role of defense and defending walled cities, it would seemingly be critical that the large force have some sort of ranged capability to harass sieging enemies.

Edit: removed note about Spartans after reasonable doubt of its validity was raised in comments.

Answer 7

This isn't possible.

Simply put, it's not possible to field an army composed entirely of a single type of soldier and do well in all circumstances; there is no type of troop which is "average at all things". Different types of soldier are better at different things, depending on the situation they find themselves in. Deciding to specialize entirely in a single type of troop would allow your enemies to find the weaknesses of that troop type, and then exploit those weaknesses to destroy you.

Blocks of spear-based infantry are very strong against enemies attacking them from the front, but are weak to flanking attacks due to the difficulty they face in maneuvering. Sword-wielding heavy infantry like the Roman legionnaires are more maneuverable than pike blocks, but have less reach.

Heavy cavalry are maneuverable and good at delivering devastating charges, but can become bogged down - and charging into a pike wall is suicidal (but charging into the flanks of a pike wall is likely to result in a massacre). Light cavalry archers can maneuver well and cause damage as they run away, but lack a lot of offensive punch against hardened targets.

Longbowmen and crossbowmen have more powerful ranged attacks, but require logistical support to supply their ammunition and are likely to lack training in melee combat - and in the case of crossbowmen, they will have to spend a long time reloading between each attack, while longbowmen require years of training.

Siege weapons and artillery can cause a lot of damage to hardened targets such as castles, but it is difficult to maneuver, with larger and more powerful weapons being entirely immobile.

In general, the best army is the one that combines together the different elements available to them in a way that allows them to exploit the benefits of their troop choices and the weaknesses of their enemy's choices while minimizing their own weaknesses, and that is likely to require a combined arms approach.

Answer 8

Why not use slings ?

Ammo are rocks, easy to find and gather, basically no maintenance, people can be trained since childhood to use them. On side-arm they could use small hunting knives or close combat improvised weapon.

Does it have to be a regular army or is it composed by peasants milicia ? Because they mainly use farming tools to defent themselves, and could be asimiled to ligth infantry

The 5-10% could be the nobles people, who could afford buy/making decent weapons, spear, bow or sword, or be educated to magic use/ basic spells. They also could be you chief bodyguard troops.

Answer 9

Armies are not about weapons and armed the same way does not have to mean only one weapon. I would suggest you look at the Roman style: Vast majority of the army equipped with short sword and shield supplemented by spears. This provides a good balance between defensive and offensive postures that are missing from single weapon armies. Special forces include light and heavy cavalry and scouts/trackers.

The greatest advantage that the Romans had (imo) was not their weapons, it was their training, this allowed them to fight in units not as individuals.

Answer 10

I see 2 additional options:

1.) Greek fire, naphtha or similar, paired with shield against archers that would outrange you. Throw bombs and/or use flamethrower against poor unsuspecting attackers and enjoy the sight of chaos. Remaining 5% are light cavalry to kill or capture the slightly burnt fleeing troops. This is also useful in swamp. Now just hope your alchemists don't blow up your entire civilization and that you have enough material.

2.) Excluding fire, I would pick heavy/shock cavalry - https://en.wikipedia.org/wiki/Cataphract as the ancient version. You have a large enough area with suitable terrain for that. While all civilizations that fielded them used them as a sprinkle of elite units, this is mainly related to incredibly high cost, not lack of effectiveness. So, it isn't unrealistic because it would be bad at something but because it is far too expensive to be the main battle unit. You really need a lot of horses and a lot of smiths for that. There is one obvious weapon system that defeats them - pike. But against those, you have 5% of folks remaining. Engineers tasked with building siege weapons, removing caltrops and whatnot else. Use catapult against those slow pikes and hope they break formation, enabling you to smash through with your cavalry. This is also helpful when you want to capture a fortified position.
This option does not work in swamp, but you say the swamp is nearly impassable.

Answer 11

Repeating Crossbows, bayonets and lots of fortifications.

If the goal is to fight lots of armies, then what you need is a weapon that can take on all comers, and is easy to use. The answer is of course repeating crossbows.

Crossbows are easy to use, point and fire, and have enough variation that you can adapt them to different enemy types.

Repeating crossbows can output a lot of power, and with poison from the swamps you mentioned kill even armored men.

The repeating crossbow had an effective range of 70 meters and a maximum range of 180 meters.[7] Its comparatively short range limited its usage to primarily defensive positions, where its ability to rapidly discharge 7–10 bolts in 15–20 seconds was used to prevent assaults on gates and doorways.

They can mount bayonets on their crossbows to let them charge and injure enemies, and a well constructed enough crossbow could serve as a dual sword and crossbow, short and agile for fighting behind barricades and walls. A long enough bayonet could serve as a spear to block cavalry charges, while you pump them full of crossbow fire.

They have some advantages.

You can quickly raise a huge amount of firepower. Crossbows are easy to use, and you can quickly equip your women, children, and old people with cross bows to raise a huge defensive force, enough to output a huge amount of firepower into an enemy.

You can kill weaker forces with minimal casualties. Your superior ranged weapons can demoralize and crush weaker forces without exposing your forces to death.

They have some large disadvantages.

Repeating crossbows, or combo weapons are very heavy. They wouldn't be much use offensively due to their sheer weight. But, they're for defensive operations so that's fine.

They're inaccurate and not very penetrating. Supply lines would be hell. This is less of an issue defensively, as they can supply everything from cities.

They have trouble with heavily armored troops. Armor can block crossbow fire, and ancient crossbows were not the most accurate weapons. A heavily armored charge might break them. Fortifications would mitigate this, but then they face the risk.

You have trouble with longbows. Longbows are hard to make, and train for, but with their superior range and accuracy they can pepper you with fire and stay out of range.

Your special troops would be wagons with massive crossbows.

Not as fast or as agile as mounted cavalry, these would nevertheless allow you to deliver a lot of heavy firepower where you needed it. Massive bolts to rip through enemy troops, armor, or pick off fleeing enemies. This could also serve to disrupt enemy fortification and heavy mounted enemies. Beasts of the field or oxen could also be used, as the main ideal is heavy firepower.