Comment by beloch | Hacker News Reader

Comment by beloch | Hacker News Reader

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Look up the Battle of Cannae, wherein Hannibal successfully encircled a force of approximately 80k Romans and killed approximately 70k of them. This wasn't bowmen vs infantry but, primarily, infantry vs infantry. The battle was effectively won once the encirclement was completed, but killing people in close quarter combat is an agonizingly slow process unless there's a rout. Encircled soldiers can't rout. The slaughter continued until darkness, and only after dark did the battle cease, leaving some survivors (night battles were exceedingly rare in antiquity).

Imagine being in the middle of an army that is being driven into a more and more compact mass of panicking humanity, knowing that you've lost and are doomed to die, but that death does not arrive for, possibly, the better part of a day! Livy reported of the Romans that, "Some were found with their heads plunged into the earth, which they had excavated; having thus, as it appeared, made pits for themselves, and having suffocated themselves."

I'd take one good charge and death by a storm of arrows over that any day.

I actually thought of the Battle of Cannae during the episode of Game of Thrones Battle of the Bastards.

Sure. I'm sure you think of it during most medieval show that has some sort of warfare, some variation of it is almost always featured, though as far as I know tactics similar to that had been used long before that particular battle.

Encirclement Is very old tactics the medieval period actually used this and much more modern tactics effectively combined arms warfare.

Encirclement was just the outcome. What was really interesting to me in the battle of Cannae was the feigned retreat.

Why would being surrounded matter in this case? It’s not like the Romans ran out of food or weaponry.

Actually, if infantry groups large enough to maintain a front meet hand to hand on flat terrain, and the soldiers are of similar strength, losses should be about 1:1 and proportional to the length of the front because the larger party can’t put more soldiers near the front than the smaller one (if anything, the larger party would be able to give its soldiers more rest)

(If the smaller group gets too small to easily keep up a closed front, this changes; it gets torn apart fast because each defender would be needed almost all the time to prevent the front from breaking, and also would face >1 enemy. Guns, spears, or artillery change things even more, as they allow the larger group to land more blows per enemy head than the smaller group _above_ the proportion of the sizes of the armies)

So, all else being equal, the much larger Roman army should have been able to break that encirclement.

⇒ either things weren’t equal (were the hastily created Roman legions less experienced or less well trained?) or was panicking the important factor?

Take 100 sword bearing barbarians and form them in a circle shoulder to shoulder facing inward. Take 120 legionaries and form them in a circle inside the barbarians circle, also shoulder to shoulder but facing outward. The legionaries circle can't hold 120 men, or even 100, it's likely closer to 90, so the other 30 legionaries have to wait inside the circle.

So now it's 100 vs. 90, each of the fighting legionaries on the circle has to fight the man in front of them, while avoiding a thrust from the extra men along side them. Meanwhile the other 30 wait, listening as their comrades are being slowly killed.

But it never begins as a circle. Instead the solid line of legionaries is outflanked, barbarians rush around them causing panic in the rear lines at both sides. The men at the end of the line are butchered quickly, they can't fight the men in front of them while being attacked from the side.

So masses of romans at the ends of the lines were killed and the survivors on the ends ran back behind the center of the line until they formed a tightly bound ball of men, those buried in the center unable to fight, while the now greater numbers of their opponents are free to attack the outer line from all directions.

I thought the Romans had good luck with the 'turtle'? Where they formed a square shield wall with archers inside...

No time to form a turtle formation. Also I think that was only used when storming walls.

”The legionaries circle can't hold 120 men, or even 100, it's likely closer to 90”

For that to happen, the radius of the circle of Romans has to be ¾ of that of the circle of barbarians. With 2 meters distance between their heads, that would make a radius of 6 meters vs 8 meters, and circumferences of 36 and 48 meters, or about half a meter per man. Tight, but yes, at that scale, the outside army has the benefit.

These armies were larger, though. At 900 defenders and the same distance between the lines, there would be 930 attackers. At 9,000 defenders, there would be 9,030.

”barbarians rush around them causing panic”.

Panic is what I put in as an option, and what surprises me. I would hope the Roman army, knowingly marching into enemy lines in a fairly shallow column would be prepared to see enemies appear in their flanks.

What you describe must have happened, but I don’t see how an army that large with such superior numbers would get there, unless its soldiers weren’t as good as those of the enemy in some way by quite some margin. Lack of leadership decreasing soldier resilience? Lack of experience?

First they weren't professional soldiers. They were farmers. Professional or not, being outflanked is terrifying.

Second, the troops weren't identical. Hannibal had very experienced mercenaries with all sorts of different weapons, and his cavalry was far better than the romans.

Third, Varro thought he'd crush the center of Hannibal's line and force the Carthaginians to panic as they fall back into the river by stacking Roman forces far deeper than usual. That shortened their line and made it easier to outflank. And pushing back Hannibals center naturally pushed his forces into an enveloping crescent shape.

Fourth, the Roman infantrymen didn't know what was going on. The wind was in their face, blowing dust. The Carthagian army made enormous noise as it attacked. The roman troops were thirsty and hungry, Varro had drawn up his troops early before they could eat or drink.

Lastly what destroyed the Roman cohesion was the loss of their cavalary. The Numidian cavalry crushed them on one side and barbarian cavalry crushed them on the other. Then the carthagians could wheel and attack the roman infantry from the back and sides, while their cavalry cut off any retreat.

Really puts a point of the phrase "to bury one's head in the sand" - doesn't it?

Thanks! Another great overview by this guy https://www.youtube.com/watch?v=MroGPObEZzk

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