Why were troops with bayonets often effective against enemy cavalry even though the bayonet was a “secondary” weapon?

The bayonet was introduced in the late 17th century as a knife (later a short sword) attached to a musket, to enable the musketeer to protect himself when reloading their single-shot weapons. As such, it was something of an "adjunct" weapon to the gun itself. http://en.wikipedia.org/wiki/Bayonet

Anti-cavalry tactics in the late 18th, early 19th century often consisted of musketeers with bayonets "forming square" to resist cavalry charges. These resistances often succeeded, whereas during earlier periods, such as the Middle Ages, soldiers armed with "pole" weapons such as spears were usually at a disadvantage versus cavalry (unless there were compensating features such as rough ground or bad weather), even though these were their "primary" weapons.

What gave soldiers with bayonets (and muskets) their effectiveness? Did the one volley of musket fire sufficiently disorganize the cavalry to give the bayoneters their advantage? Did the presence of muskets force a change in cavalry tactics (e.g. the removal of armor) that favored the musketeer? Were they just better-drilled soldiers than the spear carriers?

• Why do you assume that spearmen or pikemen were "usually at a disadvantage versus cavalry"? I can only see cavalry having the advantage, in a field engagement with a pike block, if the infantry started to rout, in which case their armament would end up on the ground anyway. – user4139 Feb 16 '16 at 21:23
• @JonofAllTrades: In the Middle Ages, "cavalry" consisted of "spearmen" with lances. That is, spearmen on horses charging 15-20 mph versus "standing" spearmen. The latter were at a disadvantage because they weren't moving. – Tom Au Feb 16 '16 at 21:55
• I am familiar with the meaning of the word, thanks. Given that there will be several more pikes than lances in each meter of front, should the cavalry choose to charge braced infantrymen, being the moving party isn't much consolation when you've been skewered. – user4139 Feb 16 '16 at 22:18

The situation is complex. While the pike-or-equivalent must be of a sufficient length and density to be effective against cavalry, the longer the weapon the more difficult it is to adjust formation and facing. Cavalry's most effective weapon on the battlefield is its speed. A mass of spearmen facing one direction are easily flanked and broken up, and then worse, by cavalry that can find its flank.

Note that an infantry square from the Napoleonic period (open, as practiced by the French or British) comprised 2 or 3 ranks of densely packed bayonets, backed by additional ranks of musketeers and pistol-armed officers loaded and primed. The bayonet wall was to keep the cavalry at bay and prevent an overrun, while the muskets and pistols behind kept cavalry from trying to squeeze in with the sabre or lance.

The closed square practiced from Brandenburg eastward, and by skirmishers caught in the open, was less well organized and a bit more vulnerable, but could form significantly quicker. (Even 15 or 20 seconds faster is important when a half-ton of horseflesh plus rider is approaching at 25 mph.) The additional speed was essential against the very fast light cavalry of the steppes, who also fought in looser and less organized formations and were less able to attempt square-breaking.

Also the professional training of the small late 17th century to early 18th century gave units the experience and morale to stand firm as a cavalry charge approached. The medieval formations of spearmen were generally levies, not trained troops. Prior to that of course, the Roman legions and Greek phalanxes were extremely effective against the stirrup-less cavalry that they faced. That is the raison d'être of Republican Rome's Triari.

• Yes. Well described. – Rohit Sep 30 '14 at 6:17
• Good, detailed answer. One addition: cavalry were often much heavier in medieval ages. Knights and heavy cavalry with long pole-arms were typical to charge on infantry. To beat them, the infantry needed to be equipped with long pole arms and organized formations. The cavalry in XVIII-XIXth are more often light cavalry, which can perfom much less formidable charges and often have sword/saber as main weapon. Their primary role was not to break through enemy lines. – Greg Feb 12 '16 at 3:18

An important aspect that seems to be neglected in many of the answers here is that while technical aspects cannot be completely dismissed, they are secondary to other concerns.

To be specific, the primary weapon of heavy cavalry is its momentum, while heavy infantry (among which musketeers from 18th century onward are counted) relies on its discipline in formation and the ability to stand its ground.

The reason why a spear, pike, halberd, or equivalently a musket with a bayonet, are a foil to cavalry is that if the infantry wielding them maintains discipline and remains in formation, cavalry cannot simply trample them and needs to resort to either harassing the formation or fighting in close quarters. If that happens, individual riders are at a disadvantage, and there is decidedly fewer of them than there is of the infantry.

Presenting an impenetrable wall of bodies and steel to a cavalry charge and thus robbing it of its momentum is in fact the way to deal with heavy cavalry. Besides ancient phalanxes, this has been successfully attempted by Scottish schiltrons, Swiss pike formations or Hussite wagon forts as early as the 13th century and spelt the end of heavy cavalry dominance on the battlefield. This was later cemented by Spanish (and later German) tercios and by the time of the Napoleonic wars, a cavalry charge against well-formed infantry was essentially hopeless.

Now, not to diminish the significance of bayonets, there are several important contributions that they, and related technologies, made.

• First, the combination of bayonet and a musket meant that you no longer needed to maintain separate missile troops and heavy infantry (where earlier it was not feasible for an archer or an arbalesteer to carry a pike around). This permitted the transition from earlier pike-and-shot formations to homogeneous musket infantry.
• Second, the specific technology of a socket bayonet mitigated vulnerability of infantry to sudden charges, either by cavalry or other infantry, because you could have your bayonet on and be ready to defend yourself in close combat while still being able to shoot (even if muzzleloading was made a bit more difficult by the blade sticking up from the end of your barrel). This, some historians claim, is what made the difference against tactics like the Highland Charge (see Battle of Culloden).
• Third, in comparison to earlier missile weapons, a musket was something you could train very nearly anyone to operate. Where getting reasonable proficiency with a sling would require a lifetime of training, with a bow, years, and with a crossbow months, pretty much anyone could be drilled to load and shoot a musket in a week or so. This in turn prompted the development (or more precisely, refinement) of standardized infantry drill for fighting with a bayonet, marching and maintaining unit cohesion, all of which are crucial when facing heavy cavalry.

So to conclude, it was not really the weapon that made the difference (although it helps to be able to shoot the horse from under a charging cavalryman - a lot easier and just as deadly alternative to trying to shoot the cavalryman himself), but how it was being used. Earlier heavy infantry tactics, such as pike squares, were reasonably effective when well executed, but the proliferation of the musket with a bayonet, as well as of thorough infantry drill, only finally made sure that in a head on confrontation, cavalry was rendered impotent.

As an addendum, remember that this did not make cavalry completely useless. Well into the Napoleonic wars, cavalry would play an important role in scouting as well as pursuit, and it was still possible to find infantry that was either not disciplined enough to withstand the primal terror of a cavalry charge, or was simply caught by surprise. It was also possible to get plain lucky and have the infantry square break at an inopportune moment, as happened at the Battle of Garcia Hernandez.

Furthermore, an infantry battalion that has formed square is effectively pinned down, and the massed formation makes it an easy target for artillery (because any good hit will necessarily take out more of the enemy) or infantry (on account of the square being a lot harder to miss, even with a musket). Following best practices for combined-arms tactics is vital.

• Welcome to the site. An upvote for a good answer. – Tom Au Sep 30 '14 at 22:37
• Overall very good, but I take exception to this in the last paragraph: "an infantry battalion that has formed square is effectively pinned down" French Imperial Guard battalions routinely marched around the battlefield in hollow square, and as did some other elites of the period from time to time. It is a "miniatures misconception" that units in hollow square were immobile - that only applied to units in closed square such as Austrian and Russian masse. – Pieter Geerkens Dec 9 '15 at 23:02

For a case study reference, this may be relevant.

This is from Battle of Waterloo, when Ney assaulted Wellington's centre in the French cavalary charge

""Initially Milhaud's reserve cavalry corps of cuirassiers and Lefebvre-Desnoëttes' light cavalry division of the Imperial Guard, some 4,800 sabres, were committed. When these were repulsed, Kellermann's heavy cavalry corps and Guyot's heavy cavalry of the Guard were added to the massed assault, a total of around 9,000 cavalry in 67 squadrons.

Wellington's infantry responded by forming squares (hollow box-formations four ranks deep). Squares were much smaller than usually depicted in paintings of the battle – a 500-man battalion square would have been no more than 60 feet (18 m) in length on a side. Vulnerable to artillery or infantry, squares that stood their ground were deadly to cavalry, because they could not be outflanked and because horses would not charge into a hedge of bayonets. Wellington ordered his artillery crews to take shelter within the squares as the cavalry approached, and to return to their guns and resume fire as they retreated."

""If infantry being attacked held firm in their square defensive formations, and were not panicked, cavalry on their own could do very little damage to them. The French cavalry attacks were repeatedly repelled by the steadfast infantry squares, the harrying fire of British artillery as the French cavalry recoiled down the slopes to regroup...."

• Why would squares be vulnerable to infantry? Against artillery, obviously. – Tom Au Sep 30 '14 at 13:55
• That is a question to think over – Rohit Oct 3 '14 at 7:16
• In the square, half to three quarters of the infantry is facing in other directions than at your line and cannot fire at all. This is quite an advantage to you. – Oldcat Feb 18 '15 at 23:14
• Target saturation via volley fire. A long front to a short front increased the chance of hitting. – Alan Kael Ball Mar 12 '15 at 14:53
• @Tom Au: Because "horses would not charge into a hedge of bayonets", but humans will. – jamesqf Feb 12 '16 at 19:17

"What gave soldiers with bayonets (and muskets) their effectiveness?"

I'd say the main reason they were more effective against circa-18th Century cavalry, than typical pole-armed footmen were against mounted knights, was the lighter armor of the cavalry, and the attitudes and training of the time.

Medieval knights were a dedicated warrior class with heavy armor, and expected to be superior to other types of forces.

Mainly, it's quite hard to injure someone in full-body metal armor, good chain or plate, with a hand weapon. 18th Century cavalry tended to have a helmet and breastplate at most, so were much easier to wound than a fully-armored knight.

Short answer: The bayonet wasn't really a "secondary" weapon, even though it "followed" the musket. A musket with a bayonet was approximately the same length and weight as a spear, and could function in that capacity. Except that these "spears" could also shoot.

Bayonets gave musketeers a decisive advantage on open ground over other users of missile weapons that didn't have bayonets. This disadvantage held for e.g. American musketeers without bayonets early in the American Revolution, even though the Americans were (by far) the better shots. The Americans might well have been beaten by spearmen as well, but the "single shot" muskets acted as a morale stabilizer in giving British troops the feeling, "Our guns give us a "fair chance" in the shooting, while their chances "up close and personal" were more than "fair."

Likewise, bayoneters acted like spearmen against cavalry, except that the advantage of the "first shot" might have stiffened their morale. And the presence of the guns slowed the momentum of the first charge while preventing the cavalrymen from using armor.

I wouldn't say that knights were ineffective. True, you can waste your warriors in ineffective charge, but so you can do with your archers shooting out of range, or at heavy plated soldiers(war bow would not penetrate plate- they did it with mild steel and proper, hardened steel, and unless you got one in a visor, late XVth century armor was good to go). Then bow-lovers get all offended and ask, why bows were used at all then. Well heavy knights were only about 10-20 % of forces on the battlefield. Other people didn't have such good protection. And horses often weren't covered in plate...

XVIth-XVTIth century cavalry of the West was often lighter cavalry (not always, but quite often only armor they carried was cuirass and helmet, maybe some gauntlets) they main purpose on the battlefield was to support pike and shot formations and harass enemy(they often carried short fire arms), and then, when enemy was finally scattered, charging in. There is a number of factors at work here- why war was like that.

1. On average pike was longer than average knights lance, so horse would be killed before knight could reach opponents, not to mention, even if he got one pikemen, he would find himself in a forest of other pikes.

2. Training, say, a hundred pikemen and musketeers was still cheaper than giving as a reward land and titles to a knight(and by that i mean a knight, knighted individual, not a guy in armor on the horse- that one was called man-at-arms. Knights were very rare. In XIVth century in England was only about 500 real knights. In Battle of Grunwald 1410 there were only around 300 knights in army of 27000).

3. Cavalry was usually domain of wealthy- so nobility, wealthy citizens of cities and towns, and free, land owning peasants (in Poland they were called "Kmiecie", didn't find that name equivalent in English). In pike and shot era and later king was the one, who often outfitted his troops. Calvary is expensive. A row of guys with muskets is cheaper.

4. Most of the times wars were ended by taking some settlement. In other words sieges were far more prominent than field battles. To win field battle, you have to be sure of your strength. And often times that was not the case. Calvarymen aren't really good siege soldiers :) so why keep so many of them?

BUT- that is not to say that you couldn't make cavalry effective against pike and shot formations. And i will give winged hussars as an example. Battle of Kirchoml 1610- where around 3000 Polish- Lithuanian troops beat the flush out of Swedish army of 9000- 11000 in around 30 minutes. There are a number of factors at work here also.

1. Poland was very wealthy country in XVIth- XVIIth century, so average nobleman could outfit himself in elite unit gear and afford training from early age(to be a hussar, one had to train like a knight, since early age).

2. Average hussar lance was around 5- 6 meters long, longer than pike, there is a story that Lithuanian hussar killed 6 Russians with one hit of his lance in Płonka battle 1660. They also carried at least two pistols with them, so getting rid of numerical advantage of enemy wasn't so hard. They didn't just charge through. They would broke their lances, and do manoeuvre called "nazad"(basically turn around in place, forcing horse to stand on its hind legs and then running back) and ran back, for another lance, and another horse, if first one was winded. And they repeated charges until enemy was routing. They also weren't really heavy cavalry. They often had only cuirasses, cuisses, pauldrons, vambraces and helmets, so about as much as heaviest shooting cavalry of the West of XVIITh century. Their horses were light and rather smallish, so they could manoeuvre quickly.

3. As I said earlier, cavalry is a nobleman unit. It so happens, that nobility in XVIth XVIIth century in the West was around 2- 4% of society. Go and make them an army, especially that about half of them were women. In Polish- Lithuanian Commonwealth nobility reached around 10% of society...

So yes, you can make cavalry very effective, but there is so much factors here, that i really am not surprised that West would rather go with pike, than bastard grandchild of a knightly cavalry :)

So after this long entrance, why was bayonet so effective? Others nailed it, give or take. Average armor was given to a trooper rather than his horse, and most of them rather carried fire arms, even long ones, like Dragoons for example, than polearms. And since their war doctrine was to support and harass earlier, why would they change that? If i have only sabre or sword, guys with heavy "short spears" in dense formation will get my horse first. And combination of two types of soldiers into one (pikeman and musketeer) also made things easier for generals, as you didn't have to manoeuvre with two units.

But there are always exceptions, and ways of dealing with infantry like that. "Los Infernos Picadores" :D yep my ancestors were nutjobs. I dont know if there is a good English language source, but basically they were a unit of polearm carrying (in polish "lanca". Knightly, and later hussar polearm was called "kopia"- "lance", while "lanca" is something between lance and spear. Just type "lanca kawaleryjska" in Google images if you are interested in how it looked like) polish cavalry known for their ferocity in battle. They became famous during Napoleon's campaign in Spain, hence their name

I think there were two reasons at play:

1. Musketeers were "formation troops", i.e., they were used to fighting in a close formation, standing next to each other and acting in sync. This means that when they affixed bayonets and pointed them at the cavalry, the horses were facing tightly knit line of steel and could not carry their riders close enough for their sabers to be effective. The spear/halberd carriers were more accustomed to one-on-one combat (during middle ages), so they did not always managed to stand shoulder to shoulder to meet the enemy cavalry in time for its attack.
2. Cavalry which attacked spear/halberd carriers was the heavy knight cavalry: armored man and horse, with the rider armed with a lance or long sword. The cavalry which faced musketeers was lighter (at most a cuirass) and their weapons were shorter.

Both changes were happening during the same time period, driven by the gunpowder revolution which made body armor useless and forced close formation on the infantry (to compensate for the lack of accuracy).

• This is blatant nonsense: "The spear/halberd carriers were more accustomed to one-on-one combat, so they did not stand shoulder to shoulder to meet the enemy cavalry." The phalanx is as old as ancient Greece, and the March of the ten thousand the inspiration for Philip and then Alexander. – Pieter Geerkens Aug 8 '13 at 21:55
• @PieterGeerkens: I did not say that pre-firearm infantry did not know phalanx - just that their normal tactics at THAT time was more oriented towards "free form" (I edited the answer to emphasize that) – sds Aug 8 '13 at 21:59
• In the middle ages the spear was often thrown (early) and were also often used in a tight formation to counter cavalry - as used by William Wallace at the battle of Falkirk. Fisher, Andrew (1986). William Wallace. – Kobunite Aug 8 '13 at 22:04
• Spears are never thrown. Javelins are thrown, and spears are kept in hand. The weight balance is completely different, making spears impossible to aim or throw for distance, and javelins much too light and short to be effective as a hand-held weapon. – Pieter Geerkens Aug 8 '13 at 22:08
• A Javelin is a spear. The spear adapted over time based on needs. – Kobunite Aug 9 '13 at 8:02

What I've been missing from the current answers is that early heavy cavalry, i.e. knights in armor (mail until ~1400, plate armor only in late medieval), weren't as effective as "advertised". They surely won battles but they did as one part of a bigger army. By the point in a battle the cavalry charge was ordered, enemy formations have already been "loosened" up by archer's volleys. However archers weren't supposed or even allowed to win battles. When they had done their job, they were ordered to the back so that cavalry could sack the win. Keep in mind that heavy cavalry was composed of nobles, while infantry or archers were commoners. The glory of the win would not be handed to commoners.

As a reference, look at the accomplishment of England, which was to put up more (in quality and quantity) trained archers. Suddenly knights were losing battles against archers. The rules of the game had changed and obviously they wouldn't change back. In this the story of Robin Hood, a noble archer, can be seen as a kind of PR-measure for archers. It's not surprising, that Robin Hood is an English tale.

Musketeers with bayonets are just a way to combine ranged and close-combat capabilities of archers and spearmen. However the actual beginning decline of cavalry was earlier with English longbow-men.

To complete the story of decline, what defeated the cavalry in the end was barbed wire.

• Assertions without supporting research. – Mark C. Wallace Oct 4 '16 at 11:46
• Agreed, I'm lacking references. Didn't think standards were as high as over at skeptics where every other sentence needs a primary source. The accepted and top-rated answer doesn't cite scientific research or any other source either... So what's the standard here? Is history channel's "How to win ..." series ok? I think, it's generally lacking in many aspects but the episodes on bowmen and crossbows fits historic proceedings (English success in campaigns to France, decline of armor, ...) and the likely sentiment of nobles towards ranged weapons (which made them obsolete). – NoAnswer Oct 4 '16 at 12:21
• Excellent point - community standards for citations are under discussion now, but there is a consensus that superior answers support every non-trivial assertion. – Mark C. Wallace Oct 4 '16 at 12:48
• Problem is, for a historical archery fan this is rather trivial. 175lbs drawing force (as the English longbow is supposed to have had, again see "How to win...") is enough to puncture steel plates hence knights grew increasingly obsolete around 1500 (that's BEFORE gun powder was widely available). The transition only took time, because of understandable resistance of nobles and problems in supplies for ranged forces, which were "solved" by muskets (balls and powder are much lighter and cheaper than high quality arrows). Feel free to propose or directly edit in anything you got/find. – NoAnswer Oct 4 '16 at 13:05
• Sadly, the only direct source I remember is "How to win", which I'm hesitant to add. Indirect sources (just fitting the picture) would be about: 1) Successful campaigns of England into France. I don't quite remember the name (especially in English, as I'm not native) of that famous battle I have in mind. 2) Excommunication of an English king for using crossbows against "fellow" Christians (don't remember his name either). I know this isn't really helping but opening more cans of worms. I've just not been interested in dates/names but in the role of early ranged weapons and tactics. – NoAnswer Oct 4 '16 at 13:55