In ancient warfare, or indeed modern warfare before the advent of accurate rifles, armies generally kept in some kind of formation. Well, some armies, anyway. The Celtic peoples of Roman and Greek times were exceptions to this rule. But armies like the Romans, Greeks, generally any spearmen on any battlefield, and any modern European army, all stayed as a block of troops and worked together in a distinct formation.
That's Real Life. Fiction is different. This trope describes situations where you see armies fighting out of formation which should be in a distinct formation.
That said, some things you'd expect to be unrealistic, like having soldiers wielding different weapons from each other in the same group of soldiers, aren't necessarily wrong; towards the end of Medieval warfare, knights generally fought with the support of several warriors of lower status armed with weapons, and fought in smaller units. And as soldiers were often required to arm themselves, those of lower status would often have to bring whatever they could to hit the enemy with. The warfare during The Wars of the Roses is an example. Generally though, warriors of different social standings fought separately from their collegues.
Even cavalry, who you wouldn't think of as having a formation, can fall victim to this. For example, Alexander's cavalry would have often charged home in the wedge formation.
A big exception is once battle is joined. The most disciplined forces, like Roman and Greek soldiers, would try to maintain formation under all circumstances, and pike and spear walls would likewise attempt to maintain the integrity of their formation. But war is war, and at some point the formation is going to dissolve or at least weaken. So if there's heavy melee fighting going on, it's acceptable to see soldiers duelling it out as individuals. Expect to see historians face-palming if phalangites are charging in with swords mid-melee however. Same goes for Roman legionaries willingly coming out of their famous shield wall.
A subtrope of Hollywood Tactics.
There are as many variations of this trope as there are armies. Please do some research before adding examples of this trope.
In both the comic and animated versions of Astérix, the Romans use tightly packed, highly disciplined formations - initially. Unfortunately for them, the magic potion gives the Gauls enough power to smash through the formations and then crush the legions in the chaotic melee that follows.
Played straight in Braveheart. The Scots fought as disciplined pike formations, it was their lack of armour and cavalry which made them so vulnerable to the longbow. (and what wasn't in those days?) They would not have charged wildly into battle, but advanced in disciplined rows in order to push back cavalry and infantry with massed ranks. The Scots didn't win the battles where they managed to close for battle with the individually more skilled English knights for no reason.
It inadvertently shows the effects of not fighting in formation. We're supposed to believe the Scots "won" at Stirling because the few dozen guys still standing at the end are Scottish — even though losing as many soldiers as they did would be a catastrophe.
Only somewhat averted in the The Lord of the Rings movie - most battles quickly devolve into total chaos but the most disciplined soldiers on both sides do keep formation at least when taking an enemy charge (most notably elves in the prologue, and the uruk hai taking the reinforcements' charge at Helm's Deep).
The battle in which Sauron was originally defeated shows his orcs as a disorganised mob, the idea being that Sauron learnt from his defeat and realised he need a more disciplined army to win. In The Return of the King the orc army uses formations and is shown acting under the control of officers.
Massed cavalry charges are a peculiarly Mannish phenomenon - namely Dúnedain and Rohirrim - and massed cavalry charges tend to appear only in the Third Age. The Silmarillion does not mention a single Elvish cavalry unit, not to speak about charges - Elves always tend to fight as infantry. There's no evidence that they even domesticated horses, much less rode them into battle. It is appropriate to think that Men are far more formidable as enemies to Orcs as heavy cavalry than Elves - even the Noldor - as infantry.
In 300, the Spartans alternate between fighting in formation and fighting out of formation; notably, while fighting the first persian waves they fight in a tight phalanx formation, and break once they've killed the majority of the Persian troops to charge into them. Later when the Persian cavalry arrives, the Spartans adopt a tight arrow-shaped formation. The Spartans have some trouble fighting the Immortals later on until they manage to form up into a phalanx when the Arcadians distract the Immortals, and they also use a shieldwall when fighting the Persian elephants. The only times the Spartans are shown taking losses are when they fight outside of formation, such as initially against the Immortals, when the grenadiers attack, and when a few Spartans range out ahead of the rest of the formation and get hit by cavalry.
And, of course, its possible that they never actually broke ranks at all, and it was just a tactic by the Unreliable Narrator to make the deaths look more heroic.
Averted in Troy, in the Battle by the gates the Greeks charge at the Trojans in a mass and we see a frantic Odysseus shouting at the men to get into lines, to no avail and we see them forced back with ease by the Trojans, who stand with shields linked in clear formations
In the opening battle scene against the Germanic barbarians in Gladiator, the Roman legions advance in a decent formation -if a bit crooked due to rough terrain- until the German horde smashes into them. When that happens they immediately break up into a swirling melee. Although they win the battle, the scene does (perhaps unintentionally) illustrate the reason formations were so necessary to the Romans in the first place- in the morass of single combats that followed, the huge Germanic chieftain is almost unstoppable until he's brought down by sheer weight of numbers, demonstrative of the manner in which the powerful but undisciplined barbarians made war. There is a reason why the Romans had a (paraphrased) saying: "The Gauls will break in five minutes against a Legion shieldwall, but that wall needs to hold against the Gauls for five minutes."
Inverted later on in the movie, when a bunch of gladiators form a defensive circle to avoid being slaughtered by chariots.
In the 2010 Robin Hood, you see a line of defenders form a spear wall behind their gate. when the enemy horses drive through...they're gone. in other battles, you see French soldiers make a few thin lines, but they dissolve before the enemy is within striking distance at no provocation. so, there were formations, but they never got used.
In the battle scene early on, which is a border skirmish between one of the Alethi highprinces and a rival highprince from a neighboring kingdom, both sides' troops are largely undisciplined spearmen, and when the battle is joined it becomes a chaotic melee where the battle mostly consists of small groups of soldiers are fighting at random. The only spear unit that fights effectively is Kaladin's platoon, who maintain a tight, wedge-shaped formation that easily drives back anyone attacking them.
Later on, during the battles on the Shattered Plains, formations of professional soldiers are shown in direct contrast to the undisciplined border skirmishes. Alethi soldiers fight in close, cooperative formation to defeat the Parshendi, who are a force of extremely mobile heavy infantry able to leap across the chasms and are much stronger and tougher than human soldiers. Only by maintaining their disciplined formations are the Alethi able to match them, and late in the book, when an Alethi force has to desperately charge into and push through a massed Parshendi force to reach the only safe bridge off a plateau, they suffer tremendous losses due to the breakdown of their formations.
The Parshendi themselves are noted as not using formations and instead fighting in large groups divided into "warpairs" of two Parshendi fighting together. They're able to make this work through their aforementioned speed and strength, coupled with the fact that the Parshendi are inhumanly well-coordinated due to how they communicate purpose, intent, and emotion through a series of universal "songs." And then in Words Of Radiance, the Parshendi do start using formations when they begin manifesting their "stormform" bodies and become Voidbringers, and use them to channel lightning and begin creating Everstorms.
Mostly averted in The Warlord Chronicles, a realistic telling of the Arthurian mythos from the point of view of a warrior who starts off as an ordinary spearman and later becomes one of Arthur's lieutenants. Fighting in a shield wall and the need to keep it tight are discussed at length, as are the consequences when formation isn't kept or a group of soldiers get cut off from the shield wall. However there are a few occasions where a maddened charge that completely breaks formation destroys the opponent's shield wall, and there are groups like the Blackshields, (a group of Irish berserkers and raiders) whose strategy consists entirely of charging at opponents while screaming at the top of their lungs and slaughtering anyone who stands in their way. As the Blackshields are ancient Celts, that's simply Truth in Television.
It's also worth noting that in the first book the narrator admits afterward that he spiced up the story because the Queen that he's telling it to expects Rule of Drama to be in effect, and that there's no way that particular battle would have happened as he originally told it.
Discussed in the Belisarius Series. In several instances the enemy cannot keep a formation(because they are ill-trained, and in both Constantinople and Alexandria they are rioting thugs under enemy pay). However the Romans, being Romans definitely keep formation.
Discussed in the Codex Alera series. Tavi, who is a skilled and experienced swordsman, is baffled at the brutal and simplistic fighting style that the Aleran Legions use while training to go under cover as a Legion officer. Maximus, who is training him, explains that Tavi was taught as a spy and agent of the crown, and learned how to fight as a single combatant or with a small group in close quarters or street fighting, and how formation fighting as part of a large unit is a completely different monster. Maximus has to teach him how to use a shield and sword as part of a battle line, where he must always use his shield to support his fellow soldiers, and how the ugly and basic stabs and cuts with a short sword are best employed in a battle line. Throughout the series, this training proves true: Aleran soldiers fighting in shield walls prove to be immensely tough and difficult to break, even against enemies like the Canim (massive, super-strong wolfmen) or the Vord (a Horde of Alien Locusts).
Averted in Rome. Caesar's legions are shown forming a testudo (turtle, wall of shields) and rotating their troops in a disciplined way. Legionnaire Titus Pullo leaves the formation and is punished for that.
Played with later at the battle of Philippi. Both sides start in organized formations but the battle later degenerates into a massive confused brawl. We can later see that Octavian and Anthony's forces have the clear upper hand when significant numbers have reformed into tight formation to advance toward the command position of Brutus and Cassius.
A weird example with Spartacus War Of The Damned. On the one hand, both the Gladiators and the Romns typically fight their battles against each other in 300-esque one on one duels, with the Romans naturally getting slaughtered. One the other hand, every time the Romans DO fight in a tight formation (like in the finale) they utterly curbstomp the gladiators. So possibly deconstructed?
During the first battle in Vikings, a relatively small Viking raiding party is attacked by numerically superior Saxon force. The Saxons play this trope dead straight; their entire strategy consists of firing a single round of arrows at the Vikings and then wildly charging en masse. While the Vikings have a few small Hollywood touches, they keep a tight and orderly shield wall, have people in reserve to come forward and hold the wall if someone in front dies, keep archers behind the wall and then lift them up on shields to fire over the heads of their own men into the enemy, etc. The result is an utterCurb-Stomp Battle: the Vikings annihilate the enemy force, aside from a few commanders who flee on horseback, while suffering all of 2 casualties.
Averted in the Warhammer Fantasy Battle tabletop game. All models in a unit must remain in base contact with each other at all times, with the exception of Skirmish units, which can be space apart while moving, but even must get into formation when making or receiving a charge. While skirmishing units have a serious mobility adventage, the ranked soldiers gain a "rank bonus" when calculating the winner of a fight, making large, ranked units very difficult to shift. Skirmishers or lonely heroes engaging a ranked unit in a frontal assault are likely to be pushed back even if they deal more damage.
And almost every unit has soldiers equipped with the exact same weapons, except for the command groups, though that may be the player trying to cut down on bookkeeping more than anything else.
Sometimes averted and sometimes played straight in Dungeons & Dragons. Hobgoblins in the 4th Edition, especially, stick next to each other, and defenders usually need to stay near their charges to protect them. On the other hand, packed formations are very vulnerable to flashy area of effect magic.
Played straight in all The Elder Scrolls games. At first, it appears to be simple Gameplay and Story Segregation when the greatest in-game battles are all depicted with no formations at all. However, given the power that mages can wield in the game, a tightly packed formation could be obliterated with a few area-effect spells.
Background material found in the games do reveal that military units such as the Imperial Legions have formations such as shield walls.
Thoroughly averted in Total War, which demonstrates why this is a bad idea. You see you get several units who stay true to this trope... and they tend to get massacred horribly in melee. Equally going into scatter formation and then charging is a good way of getting your soldiers killed off. Generally, units that were in formation are and units that shouldn't be in formation aren't.
However, urban combat turns your nice, neat formations into a chaotic mess, especially if you're ordering more than one unit down a street at the same time. In that case, your soldiers turn into a tightly-packed mass of swords, spears, and other pointy and/or bladey instruments of death. This can be both good and bad; bad because your troops are mixed and you've got archers with daggers fighting alongside heavily-armored knights, and good because you can pack more pointy and bladey into an area and meatgrind enemy troops under a morass of troops. Just hope the enemy doesn't have catapults or cannons.
Formation can become critical depending on the situation; many units are able to adopt special formations as needed. Most well-trained spear units, for example, can form up into a sciltrom, which is essentially a spearwall circle, which is utterly devastating against cavalry and will let the infantry hold out better against enemy infantry, at the penalty of very slow movement, very small coverage, and low offensive ability. Pike units can form spearwalls, which cannot charge but when are set up can obliterate charging cavalry and hold off assaulting infantry, and press shorter-ranged enemy infantry back. Certain heavy infantry units can form shieldwalls, which can charge and break through enemy infantry formations. Many heavy cavalry can form into wedge formations, letting them charge straight through enemy infantry or cavalry groups and split them apart. Line infantry can fix bayonets and form square to guard against cavalry.
This trope was a major bug at release for the second Rome game, all units instantly broke formation as soon as battle was joined.
Played with in Dragon Age: Origins during the battles at Ostagar and later Denerim. In the Ostagar battle, the Ferelden troops charge the darkspawn (who have no formation at all beyond being a simple wave) in a rough line and meet them outside the fortress walls. Also, Loghain's troops are shown to be gathered in a sensible, if very thick and deep, formation. The battle devolves into an uncontrolled melee as it progresses, but this is partially because Loghain betrays the king and retreats, leaving the king's army to be slaughtered. Later, in Denerim, when Arl Eamon's troops charge the darkspawn, the initial charge is shown as a block of soldiers advancing in a tight formation when they hit the darkspawn lines. Weapons are also notably very mixed in the Ferelden army, with sword-and-shield and two-handed weapons troops mixed together, though it is implied this is because Ferelden's army isn't the most cohesive (and possibly quickly conscripted). We do see single-weapon formations a few times in the game, most notably Loghain's army and the Cousland troops in the Human Noble origin.
The mix of weapons is actually justified in-universe - soldiers had to supply their own weapons or buy one from the quartermaster. Either way, many would have different types of equipment.
Averted in Neverwinter Nights Hordes of the Underdark with the Elistraeeite drow, who fight in small similarly-equipped units and stick to regimented formations before the Duregar Zerg Rush turns the battle into a chaotic melee.
Averted in Overlord II with the Glorious Empire. The player character is a roughly nine-foot-tall monster of a man in diabolic armor that wields equally huge and evil weapons, throws magic around with his free hand, and commands an army of psychotic gibbering minions. Needless to say, when catching small groups and individuals, the results are usually (and hilariously) one sided. Then the soldiers get into formations: shield-bearers are nigh invulnerable and cannot be individually targeted, and archers fire in uniform volleys that will devastate your horde. That is, until you make them break formation by killing their commander, siccing the wolf-riders on them, or lob a few catapult boulders/bombs their way...
Averted and played straight on Fire Emblem: Genealogy of the Holy War, where many enemy armies come in formation and try to stay on it (as much as the game design lets them), but you still see enemies scattered around like in the rest of the series.
For the player in every game, defying this trope is key to surviving the harder difficulties with minimal casualties. Fire Emblem is a strategy game, after all.
Averted in the second and thirdAge of Empires games, where several formations with different uses are available. Units will adhere to these formations to the best of their ability, ordered appropriately (strong melee in front, weak ranged in back, etc), until they engage the enemy. Played straight in the first game, before they had the things we take for granted today, like decent pathfinding and good mass-unit controls.
A staggered formation was virtually king in the second game however since it allowed you to take less area of effect damage from siege weapons with virtually no real issues (as attacking-moving melee units would have them break formation to go toward the closest target which will stop enemies from slipping by to the best of their ability regardless of how close the formation was before). In the third game, other formations became more useful - a packed line formation could be better for musketeers attacking cavalry in the third game due to being more able to use their hand-to-hand attacks easier when the cavalry close in which are superior against them as opposed to shooting. Still, the light infantry of the game tend to be always pitiful in melee compared to firing from afar, meaning a spread formation remained the only logical thing to use for them to reduce area of effect damage and causing less ranged units to be forced to use melee against a unit next to them from being more spread out - especially since everything was Friendly Fireproof, even firing into a melee.
In Guild Wars, everyone seems to fight in small, loosely-formed squads. Since due to area-of-effect magic most players deliberately avoid standing too close together, this may be justified
The sequel Guild Wars 2 needs formations for they World vs World-fights (a real-time strategy and tower defense mix for a MMORPG). Since moste forces are defined by random players, they tend to follow this trope. However there are basic formations which the tougher classes stick close to the team leader and the ranged fighters forming a semi cirlce around and barraging constantly onto the leader's position. This is made possible with an easily spottable standard hovering above the leader.
In Dwarf Fortress, a melee dwarf will charge an enemy as soon as it gets close enough. Situations this leads to: lone charges on enemies large enough to use a dwarf for a football, ignoring sniper-class bowmen in favour of their unthreatening bodyguards, ignoring specific kill orders in favour of the closest opponent, and never ever retreating (or even following a 'move' order) as long as there's something to attack. Ranged dwarves who've run out of ammo consider themselves to be melee dwarves. Since they're usually equipped with leather and bone and have no combat training, this ends about as well as you'd expect. Really, the best you can do is station the lot of them around a corner somewhere and wait for enemies to walk into the mobile meatgrinder.
Of course, with enough training and sufficiently legendary equipment, a lone dwarf champion charging into a mass of besieging goblin forces can actually work.
Averted in Warhammer: Dark Omen: Regiments move and fight in formation and a tight one defends better against charges while a loose one is better for ranged fire. If a unit routs, it loses its cohesion for a a while and it's an easy target.
The Battle for Middle-Earth had numerous formations to be used in the game, depending on the unit. Some were only capable of an effect-less loose formation, but numerous real formations such as wedges and shield walls could be used on other units.
The Battle for Middle-Earth II did a fifty/fifty with the ability to make units go into aggressive, battle and defensive stances - doing the effects of increasing damage and reducing armor and making the unit's behavior aggressively pursue enemies, neutral and making unit's behavior chase for a short time, decreasing damage and increasing armor and making the unit's behavior only responding to being attacked. While the stances loosely mimicked different formations' effects for units, stances didn't actually change units' formation. Shield wall and porcupine formations did make an appearance as the other only possible optional formations for a few units to take - two for the former, one for the latter.
Multiplayer in Mount & Blade zigzags the trope, since every soldier in the field is generally a human player. If the players manage to create formations and organize their combat, they vastly improve their chances of success. Enemy cavalry is going to pick an unorganised pack of warriors apart, but a formation with spears at the ready, watching each others' backs, is much more fearsome.
Averted in Pharaoh, where military units have two formations: A shoulder-to-shoulder line that makes them more resistant to melee (but arrows do more damage), or a spread-out formation that takes less damage from arrows but more from melee.
Getting the enemy to break formation was often an important part of real historic battles. One good example are the pike and shot formations used by European armies around 1600. Blocks of a few hundred to several thousand soldiers strong, about half pikemen and half musketeers, were formidable walking fortresses. When two of these formations came toe to toe with each other they would enter the "push of pike", a giant armed rugby scrum in which the frontlines of one formation would eventually break and fall over, leaving their comrades to scatter in disarray, chased by anything the enemy could field. To give their own forces the best chance in these engagements, commanders would try to destabilize the opposing formations before the push. This involved letting the musketeers in these formations fire at the incoming enemy, but also cavalry charges, attacks by skirmishers (more musketeers) and artillery barrages. The main formations couldn't just give quick chase to these attackers, as that would mean breaking formation and getting slaughtered. So additional cavalry, artillery and skirmisher units were deployed to hinder the opposing ones.
A pretty good example of why formations are so pivotal in battles would be how the Napoleonic Wars were fought. In the 1700-1800's, the bulk of a European (or Europeanized) army was made up of musket-wielding infantrymen, usually organized into "line" infantry regiments of about 1000-1600 men (usually less, due to casualties and disease). The biggest threats to an infantryman on the battlefield came from enemy infantry, cavalry, and artillery, and an infantry regiment had separate formations to deal with each; therefore, infantry were rigorously trained and drilled to quickly switch between them, as taking too long could prove disastrous. Conversely, using them effectively could swing the balance of a battle. The most common formations were:
Line: Two men deep, dozens or hundreds of men long.
Good For: Facing infantry (most guns exposed per square yard), facing artillery (cannonballs can hit two men at best, and usually less accurate in general given the difficulty of hitting such a thin target).
Bad For: Facing cavalry (horses would plow through infantry in line like a bowling ball through pins, and it would only get messier once the swords come out), moving around quickly (it's cumbersome to swing a line of men around, especially in combat).
Square: Regiment is in two/three ranks in a hollow square formation facing outwards, men in front kneeling with their bayonet-tipped muskets pointed diagonally up.
Good For: Facing cavalry (horses, being sensible creatures, will refuse to charge into a mass of gleaming metal spikes; as all cavalry of the time carried swords, that meant a square was invulnerable to cavalry so long as it held formation).
Bad For: Facing infantry (it's a big stationary target that can only have a fourth of its guns facing an enemy), facing artillery (a well-placed cannonball could cause a lot of damage, and a square being large and stationary meant artillery had a much easier time hitting it), moving around at all (it was possible to move in square, but only extremely well-trained infantry could do it, and that slowly).
Column: Ten or twenty men across, many more ranks deep in a large rectangular mass.
Good For: Moving a lot of infantry around fast (men often find it hard to stop or slow down when there's 20 guys behind him wondering what the holdup is), breaking a wavering enemy (a huge mass of men moving quickly towards them was often the signal for enemy infantry to leg it), facing cavalry (deployed easily into square).
Bad For: Facing unbroken infantry in line (the column quickly becomes a deathtrap, as a well-disciplined enemy would pour fire into a column at a far faster rate than the column could return it), facing artillery (a single cannon hit could cause dozens of casualties, especially when in canister range).