A Comm for Historymemes

Is it true though? In the above example, the attackers could just concentrate their attack on one side forcing the defenders to support there

Generally, there's only so much 'pressure' that can be applied across a given width of troops. While Greek and Macedonian phalanxes benefitted from increased depth (and even then, very far from a 1-1 benefit for committing more troops), as befits their tightly-packed shoving-match style of fighting, most armies would not immediately benefit from committing more troops to a portion of the line, except to relieve exhausted troops or replace losses. This is also why reserve forces are common, to shore up any unexpected weakening of a section of the army.

On the charge, some amount of advantage is gained by increased depth, such as seen in the shoving-matches of Greek phalanxes and the focus on depth for 18th and early 19th century French troops to overwhelm enemies with a bayonet charge, but there's only so much after that initial charge you can do with that depth in most cases, since people, even trained soldiers, are generally reluctant to be shoved into the metaphorical meat grinder for prolonged periods of time.

Imagine you and 20 other friends in the front line are facing off against 21 enemies, with (for the sake of simplifying the example) no room to maneuver left or right to outflank each other. Will another 20 friends behind you with swords give you an advantage commensurate with their numbers? They can't 'reach' over your shoulders while you're fighting to strike the enemies. The best they can do is wait for someone to fall, or withdraw due to wounds or exhaustion, and replace them. Which is a large advantage if your enemies lack that, but not as simple as "More numbers = more immediate pressure".

If you and your 20 original friends all rush the enemy with all your might, you might disrupt the enemy formation, allowing some of your 20 reinforcements to join in, putting the disordered enemies at a disadvantage, but that's both (psychologically) difficult to sustain, and runs the risk of your aggression exposing yourselves to the strikes of the enemy - what good is an extra 20 troops if you lose 20 troops trying to get them into a position to fight?

Wasn’t that the great advantage of the Romans that they trained this kind of stuff a lot and thus were actually able to more or less hold these formations.

Holding a rough formation isn't as difficult as it sounds - while the Romans were obsessive about it, their foes were generally clustered in more-or-less equivalent blocks, just less neat (or just as neat, in the case of fighting Hellenic foes).

The big advantage of Roman drilling was what's called in the modern day command-and-control. A pike phalanx of the kind the Hellenic states used could be committed to combat, but not easily adjusted. Romans trained to respond with small units (maniples of ~160 in the mid-Republic, cohorts of ~800 in the Late Republic and Early Empire) to take advantage of changes in the battlefield. Roman troops could (and did) reorient and reorganize themselves as developments in the battle occurred.

At the Battle of Cynoscephalae, a small Roman force (around 2,500 men, or 10% of the army) saw changing battlefield conditions and made an obvious choice to take advantage of them ("We are now literally behind the enemy, it would be simple to run into their rear and rout them").

However, many ancient armies simply would not have been capable of doing so - to get a large mass of men to suddenly change direction and objectives requires more than just a strong voice and the necessary authority - you need men to stay together in combat-effective groups, you need them to pass along orders quickly and coherently, and you need everyone to know their literal and metaphorical place in the new set of objectives. This is what drills and low-mid-level officers help with. In that very battle, even, the Macedonians they were facing could not react quickly enough to confront several thousand men coming up from behind them, and were utterly crushed, turning what had appeared to be a draw into a complete, war-ending defeat for the Macedonians.

But I would guess most battles ended up looking more or less like the lower example.

Very rare. Even in tribal-style warfare, like that of the pre-Christian Irish and Scots, there were generally coherent lines, with a small gap wherein individuals might duel or skirmish, retiring behind their own battle line when exhausted or defeated. People in dangerous scenarios tend to cluster around friendlies even without training, with the animal mindset of "I would like to know whoever is behind me will be safe and not dangerous".

You have to keep in mind no one had this kind of bird view and no one could directly tell every soldier what to do while at the battlefield. So every soldier in the end is just fighting for their own survival eventually resulting in chaos.

Once lines break in a battle, the side that has kept the more coherent line generally wins. If you can't be guaranteed to have a lad on your left and your right, and perhaps most importantly, behind you, you're fucked. Skill can't make up for the limitations of human senses and focus. Once the enemy can use their (safe, mutually covered) troops to isolate pockets or individual enemies, those pockets and individual enemies will be attacked on multiple sides, and that is a very difficult thing to fight off.

Hence why flanking maneuvers are so vital when they're successfully executed. No one wants to get blind-sided by someone on their left or right while they're trying to focus on the angry blade-wielding fellow to their front. And no one wants to turn to the left or right to confront a foe and get shanked by the fellow in front of them.

could just concentrate their attack on one side forcing the defenders to support there and thus weaking the line which then can be attacked in return.

You can't stack up your troops like in video games, so that wouldn't work. If the attackers were concentrating on the left side, then the defenders could breach the right side and encircle the attacking army.

Also keep in mind - you pretty much can't command your troops during the battle. Once the battle is unleashed, only chaos remains. You can only try to predict the flow of the battle and position your troops accordingly and prepare the early-stage orders.

But I would guess most battles ended up looking more or less like the lower example.

Vaguely, but definitely not in a 1:1 manner like on the dance floor

If they did that, the unengaged side would fold in and attach their side

Yes, afaik the first panel is an exaggeration too, if for some reason (eg environmental, or they are defending something close) one side forms a wall/line, you initially wouldn't distribute your (non-overwhelming) force equally along that line, that's basically just a bit more organised second panel pic.

Instead you would concentrate on one or a few specific spots to try to locally overwhelm them tho break the initial line formation (spearhead the line) & get groups of them more encircled (bce the outside curve gives you more of your people vs fewer of them in the line of fight - which is the core mechanic of the joke in this post).