The words ‘Barbarian’ and ‘Pagan’ are basically a lazy form of discriminating against anyone who isn’t from the western/roman world. So I’m focusing primarily on these tribes and viewing them all as ‘Celts’; the tribes being the Spanish Celtiberians, Gauls (Franks were post-Roman, so I’m not considering them), Germanic Celts, Britons, and Gaelic Celts. I don’t really have anything new to say in discussing the Celts. Germanic Celts were basically Proto-Vikings (as history would suggest) and so they shared similarities (wooden shield, spears, iron long swords). The Celts were tribal similarly to the already discussed Zulu and Zande; all ironage but lacking the resources to use armor or heavy weapons. Instead I want to explain my theory as to why the Roman Empire was able to conquer the Celts so well. I was originally going to describe primarily the faults of the Celts, and the best way to do that would to put them against their greatest enemy, the Roman Legionnaires.
Tribes in general are at best: a loose alliance of multiple smaller groups. We see this with other tribes around the world. Not all Native Americans are Buffalo Hunters (Aztecs, Mayan and Incas made cities and Flint/Indian Corn was used by New England tribes that farmed), not all Buffalo Hunters were Sioux and not all Sioux were Lakota. This disunity made mobilizing large armies against invaders significantly difficult; especially when other tribes might still threaten you or defect to the invaders (the Beaver Wars is a good, but not the only example of Western colonists influencing Native tribes to declare war against each other). The Holy Roman Empire was so fragmented by this tribalism mentality that it had about 1800 different states: basically every town was its own government. Napoleon then came by and ate up the crumbs, giving future Germans like Otto Von Bismarck the idea to unify and not get screwed over again.
Tactics and Discipline
Celtic history is hard to analyze; considering that Celtic records and writings were scarce (many tribes had no written alphabet at all), not all tribes had the same mentality, and Roman propaganda dehumanized the Celts (the concept of ‘Barbarian’ came from the racist stereotype that Celts were so primitive and stupid that their only language was to bark “BARB BARB BARB” like a pokemon). But from what I understand: Celts would frequently just charge and battle-cry at their enemies and hope for the best. Now Celts could indeed form good tactics; The Battle of the Teutoburg Forest was one of the most famous ambushes and Roman defeats in history. However the Germanic leader, Arminius, ironically grew up in Rome and so these tactics were more Roman than Celtic. Compare this with the Battle of Watling Street: where Boudica led her army into a narrow wedge that gave the Romans a tactical advantage, causing the Celts to rout and get surrounded: despite facing a smaller Roman force. Celts were indeed brutal warriors; but Romans had discipline and order. The Roman shield-walls stayed strong and stable in the majority of their battles: strictness was essential. Celts meanwhile say “Screw it: LEEROY JENKINS!!!”
Intimidation and Armor
Intentional nudity? You would think that a bear or wolf skin pelt would be the recommended outfit. As mentioned before; each Celtic tribe is different in terms of culture and economics. So let’s first look at this idea of a COMPLETELY unarmored Celt before discussing what armor some might have had. If you ever seen a Roman nobleman; you see the toga covering their entire body, their face normally shaved, and their hair short. So proper, so clean. Romans did their best to look as un-barbaric as possible. Then we look at a stereotypical Celt: at least 6ft, showing ALL of his jacked muscles, probably having as much hair as Gimli, and covered in war paint, while raging and roaring like a bear. Now imaging this maniac charging at you. Now imaging this: times hundreds. That would be a scary charge wouldn’t it? Sure; but let’s consider that you are a soldier who is brave and disciplined: what are you even looking at here? Simply put, an easy target. The Celts HAD to be scary, it was their only true defense for the common Celtic soldier. The Romans knew that so long as their maintained their line, this charge would bounce right off them. We do see Native American, African and Polynesian tribes also lacking armor: but their climate or their competition made armor irrelevant. If it’s too hot to wear armor, you don’t have the resources to make armor, and the other tribes have no armor: you don’t need armor. The Celts aren’t in this situation however. The Romans used their logistical advantages to make and maintain superior defenses. What armor did they have? Well chainmail did sometimes exist. Unfortunately chainmail offers virtually no stabbing resistance: and the Gladius and Pilum are both thrusting weapons. So what else is there? Well leather is an option, although inferior to chainmail. There’s a large leather belt… which isn’t protecting vital organs so… what’s the point then? And you got a small metal cap: well it’s better then nothing; but if you can’t strike the crown of the skull, then just swipe the side of the head or strike the face itself. This cap doesn’t protect much at all. The shield is however impressive. As mentioned before: Celts influenced Vikings, and both have wooden shields. Sadly, the Pilum is basically the ultimate anti-shield weapon, and when you have almost nothing left beyond that: you’re an easy target. While both sides have Javelins: the Roman Scutum is curved and the Celtic spear has a standard spear head (sometimes wavy to make the cut extra nasty). The Romans can deflect Celtic Javelins, the Celts can’t do the same against a Pilum.
The Goths did conquer the Romans, yes, but Rome did not age well. The massive size of the Empire meant high costs and high populations of Non-Romans. The Western Roman Empire began to resemble the barbarians that they conquered; ironically making Rome become more barbarian. And as with any Empire, it overextends and fizzles out. This affected the military; and so the Legionnaire no longer used Gladius and Scutum but the Celtic Spear and Shield. It was no longer Roman vs barbarian but barbarian vs barbarian. I have nothing against Celts, I am interested in Celtic culture and I LOVE their music. But no matter how you look at it, the Celts were relatively primitive compared to the Romans; either due to logistics, disunity, warfare, or even mentality of being a civilization. International politics is an arms-race in every category; influence, power, economics. If you can’t keep up, even if you are cultured, even if you are brave: you will be crushed.