On conducting historical research into ancient battlesites

[Erpingham]

But not on the actual battlefield, surely?  From what I can make out the fashion was to encamp at a convenient location within five or so miles of the enemy and then march to the battlefield when the opponent did (or ideally just before).

Medieval armies often fought closer to their camps.  Some armies in fact routinely used their baggage camp as a defence to help cover their rear (e.g. Flemings, English, Burgundians).  But these were much smaller armies and relied on laagered wagons rather than entrenchments for their marching camps.

[Jim Webster]

You work out the size of a camp for 200,000 men and their baggage etc. Then work out how long it takes men to march through it to get out :-)

Jim

Agreed, that's some logistical nightmare.....

Mind you, it takes nearly a day for me to get 4 people and one dog packed and ready to go camping 

:-)

People might find http://garyb.0catch.com/camp3_dimensions/camp_dimensions.html  interesting

So a camp for 24,000 infantry and 5000 cavalry would be 186,891 square meters.

An army of 200,000 would be about 7 times larger or 1,308,237 square meters which is 323 acres or 131 hectares. It's a square 1144 meters across

Note that this is Roman and therefore tidy and efficient, contained a minimum of camp followers, so a less organised encampment might sprawl even more.


As an aside if Xerxes had 1,700,000 men this is 10,590,490 square meters which is a square 3254 meters across.

Given an ox cart can do about 16km a day, the baggage would spend about a quarter to a third of their day's march in the camp :-)

Jim

[Imperial Dave]

You work out the size of a camp for 200,000 men and their baggage etc. Then work out how long it takes men to march through it to get out :-)

Jim

Agreed, that's some logistical nightmare.....

Mind you, it takes nearly a day for me to get 4 people and one dog packed and ready to go camping 

:-)

People might find http://garyb.0catch.com/camp3_dimensions/camp_dimensions.html  interesting

So a camp for 24,000 infantry and 5000 cavalry would be 186,891 square meters.

An army of 200,000 would be about 7 times larger or 1,308,237 square meters which is 323 acres or 131 hectares. It's a square 1144 meters across

Note that this is Roman and therefore tidy and efficient, contained a minimum of camp followers, so a less organised encampment might sprawl even more.


As an aside if Xerxes had 1,700,000 men this is 10,590,490 square meters which is a square 3254 meters across.

Given an ox cart can do about 16km a day, the baggage would spend about a quarter to a third of their day's march in the camp :-)

Jim

Looking at the above, a couple of things strike me...

1. It would be extremely difficult for all but the most disciplined of armies to organise that kind of encampment and movement through etc or just accept the nightmare of time/risk penalty. So, either the numbers are indeed inflated or the army keeps separate to the rag tag who sprawl some way in the distance...?

2. Jim is really Carol Vorderman in disguise 

[Patrick Waterson]

One might also note that the traditional accepted ratio of noncombatants to combatants in a Greek army (Herodotus VII.186) is 1:1, and in a Roman army considerably less (Polybius VI.27-32 and 41, detailing the layout of a Roman camp, allocates no space for camp followers, unless one counts the modest 'market' mentioned in VI.31).

People might find http://garyb.0catch.com/camp3_dimensions/camp_dimensions.html  interesting

One should note that the Richardson formula has a 'generic army' space requirement of 239,358 square feet, apparently arrived at on a basis not too different from Polybius' figures.  The site author eventually expands this to 2,131,331 square feet (an almost ninefold increase) on the basis of supposition, as the author himself notes:

"As noted above, there is no evidence for making this addition to Richardson's formula. But there is a certain logic to it. Armies would certainly know the size of the baggage train. Since baggage trains could vary in size dramatically it would be reasonable that the camp size should be changed to accommodate them."

One would expect a Roman baggage train prior to c.AD 217 to consist largely of 'Marius' Mules'.  Thereafter one might expect Roman camps to increase in size as troops offload equipment onto a larger baggage train - do we know any archaeological examples that would confirm or deny this?

The key to camp efficiency, as Polybius explains, involves having a set location for every contingent relative to the C-in-C's tent and to each other.  With this relationship mapped out, and the order of march based on location in camp, entering and exiting camp becomes comparatively painless.  Without it, even a small army is going to be disorganised and chaotic.  A force such as Attila's at Chalons, however, is unlikely to have a single, integrated encampment, rather a collection of encampments each holding a national contingent.  Hence when the army has to get on the move or deployed for battle, instead of everyone waiting while the lead contingent gets itself moving, all contingents would emerge together, or at least simultaneously.

[aligern]

Patrick, one yard might be fine for everyone packed in and standing still, maybe braced for a charge , that's dense testudine in Angl Saxon terms.  However, you need two yards at least to move. I'd suggest a bit more for men with shafted weapons, swords etc.

Roy

[Patrick Waterson]

Polybius noted that one yard of depth was fine for moving Macedonian and Roman infantry (a phalanx and legion could not close if both were standing still).  Undisciplined barbarians might require greater depth when moving, but I do not think much more, as the limiting factor is the 2'6" standard pace - any less than this and you will have trouble, but adding more space beyond 3' or so has no discernible payoff unless the men are about to throw missiles which are long enough to cause 'friendly poke' to the rank behind when the arm is drawn back to throw.  In this case a greater depth (Vegetius recommends 6' per man) is indeed desirable, but only for the missile phase.

One could with some justification suggest that an army which habitually used hand-hurled missiles might wish to deploy and advance with 6' spacing between ranks.  This would however be something of a disadvantage while the general was giving his pre-battle speech, as it would halve the number of potential listeners on a given frontage.  For this reason I suspect that deployment would be based on one yard depth per individual infantryman, with the hurled weapon users stretching out to two yards depth per man during the advance.

A further consideration, almost certainly applicable to Dark Ages armies (but not classical regulars) is that not marching in step might be expected to impose a greater individual depth simply to avoid kicked heels.  Again, this increased spacing would probably come into being during an advance rather than during deployment.

[yesthatphil]

A further consideration, almost certainly applicable to Dark Ages armies (but not classical regulars) is that not marching in step might be expected to impose a greater individual depth simply to avoid kicked heels.  Again, this increased spacing would probably come into being during an advance rather than during deployment.

Strangely, this notion is contradicted by millions of commuters every day.    They cram together much closer than soldiers keeping in step ever can ... and tend to clear tube stations faster than platoons of soldiers can fall in on disembarking the train.   If marching in step was really as essential to efficient movement as some military minds would have you believe, nobody would ever get to work on time in the world's big cities.*

Phil
*marching in step was probably invented much later than we think to enable the close coordination of men with firearms on a battlefield where it was increasingly difficult to see because of the smoke (so rehearsed drills became key skills)

[Patrick Waterson]

An interesting observation.  One might also consider events such as the London Marathon, where several thousand runners advance at speeds greater than most formed units can manage, and not in step.  Again, progress is significant but not controlled - try stopping an ongoing Marathon (or for that matter an ongoing commuter exodus) and changing its course.  A battalion of infantry doing an in-step cross-country constitutional will differ in two ways: it will stay together (essential for men in files who depend upon each other, e.g. pikemen) and it can be halted or have its direction changed by a simple command.

We could start a separate thread on the subject of troops marching in step, if anyone is interested.

[Justin Swanton]

The bottom line seems to be that whether an infantryman needed 1, 2 or 3 yards depth, an army of 20 000 or 200 000 men would have occupied roughly the same frontage. Since armies deployed a certain distance from each other and then advanced into battle there would have been plenty of space for the necessary deployment depth, which means that a battlefield that could hypothetically accommodate 20 000 men could also accommodate 200 000.

There must have been ways of organising the pre-battle camps of very large forces. Several smaller camps grouped near to each other for example. How did Napoleon manage it?

[Jim Webster]

Well traditionally Napoleon managed it by marching separately and having Army Corps converging to fight.
Interestingly whilst they could be from 5000 to 40,000 strong, 20 to 30 thousand seems to have been the more normal size.
Which rather fits in with the size of the Roman camp and army given in the example

I'm not sure we have any examples of Ancient armies who made a habit of marching separately, camping separately and combining only for the battle. Where it occurs it seems to be allies who might not entirely have trusted each other (Cathaginians and Numidians facing the Romans)

Jim

[Mark G]

briefly, Napoleon didn't manage it, he had others who managed it for him.

the largest Napoleonic battles (treating Leipzig as a group of battles, not one) were about the same size as Malburian battles, so in terms of managing armies of that size (@100 K - 150 K per side), there was nothing going on that hadn't been seen a hundred years before.

The difference between Marlburian and Frederican (apart from a @ 50% drop in the numbers of men), was that with one exception, most M era battles featured one side deployed, and the other side forming up in front of them before the battle started
(the 'basic' plan at the start of the M era wars was to have armies too big to be attacked, thus allowing sieges - which were what was thought to realy matter - to be conducted in isolation.  Marlborough shocked everyone by actively seeking battle - his allies and subordinates included)

Fred(through necessity, Prussia was comparatively short of men at all times) worked out a grand tactical change which allowed him to beat a larger army which deployed in a fixed position (as they still did at the start) by marching it quickly to one flank and then piling in on that.  Tactically, just like the M era, this still required minimal command and control - as with M, there was one general, and he wrote the plan, and it was followed.  Freds plan worked in part because of the marching drill his army had (inherited from his dad) which enabled them to move faster tactically and change facing faster than their opponent s - hence, again, armies deploying in advance of the attack and making methodical advances - slow and at a speed which could be reacted to)

The interesting change came near the end of these wars when the Austrians and French worked out new tactics in response.

The Austrians come up with converging all arms columns - not corps, but along the same idea - Hochkirk is the best example of this,  and it always caught Fred out because he was still expecting a single point of attack.   It was as revolutionary as Fred's Oblique had been - the difference being that Fred stick with his one tactic throughout ( even Leuthen was anticipated, but the younger general who said, 'he is going to do this', was ignored.)  It was also the cause of much of their failure against Napoleon, since they stuck to it even into 1809 - it was the go to plan when things got difficult and encouraged them to keep their armies deployed in a cordon, and attacking in isolation (which in short was because the French wouldnt stay still)

And the French, who in true 18th century manner, worked out the corp system and a tactical deployment based on speed of movement and on devolving command to lower levels of the army during the 7YW but shelved it until afterwards.  This was effectively on hold until the Revolution (well, it was for this short version, there is a more detailed long version which you may want to hear elsewhere).

So cutting forward, come the revolution, the French were already well prepared with this new model of warfare, and started to put it into operation.  By the mid 1790s when N comes on the scene, it was in full swing, and by 1800 when N is a 'known' major figure, it was standard doctrine.  The big change N inherited was the massed manpower which enabled him to completely was entire armies and not give a thought to where the next one would come from - no one else had that luxury at any time against him.

Where previously, the general set out deployment, stated the formation to be used, and the colonels etc just did what they were told in a methodical and ponderous way, this new way broke the army into smaller manageable Corp, each capable of fighting on its own for a day (different from Austrian columns, because they were fixed, allowing the units and colonels to know each other and to have drilled together - like the difference between a club football team and a Ba-Bas team, but without the commensurate increase in talent when you get selected for the ba-bas).

tactically, infantry marching across all but the last 200 yards in column - screened by skirmishers - and drilled to form a square rapidly if cavalry appeared on their flanks.  a huge change from an army which deployed in line, and had all its cavalry on the flank to fend off the opponents cavalry - this was something the French worked out during the 7 years war and began experimenting with immediately after.

so a brigade (or higher) could make an attack on its own, through the middle of the battlefield, without needing the rest of the army to cover its flank, without needing cavalry on all sides, and it did so at comparively high speed, to prevent the enemy reacting quickly.  that's the basic definition of what we call a Napoleonic battle, and which contrasts with the full army deployments of the preceding century.

If you look at some of the detailed descriptions of battles like Auerstadt, where only one corp fights, you can see this best.

All Napoleon did was refine the corps system as he went (e.g. Jena, the Carre system), and accept the massed central cavalry reserves (cavalry corp - in itself basically Marlburian) and the grand battery which his subordinates worked out on the field (and in itself quite late-Frederican).

N himself was a genius at ensuring his army always had the strategic advantage and the grand tactical advantage (he almost never attacked at 'evens' despite usually being outnumbered), but tactically he did sod all of note - he didn't need to.  (its interesting to note that his greatest triumphs always came in a small enclosed campaign area, and his biggest failures always came when the enemy had space to withdraw to, preventing him forcing battle on his terms)

All that guff about French attacking in column is wrong - they marched at speed on the field and then attacked in line (well, until the end, when they had raw recruits who hadn't been trained to deploy quickly enough - by which time he was relying on massed gunnery and fear anyway).

SO in a nutshell. 

Devolved command, high speed attacks against a weakened point, and massed cavalry exploitation.  nothing really knew there except the devolved command and control tactically and the devolved command and control at corp level which enabled this to work strategically on the same roads that Marlborough had used a century before.  above all, speed and many-many more good officers than your opponent.

all of which is entirely uncomparable to the ancient period- centurians and optios do not even come close.

and which is why and wargame which has Napoleonic Calvary out on the wings  and the infantry in the centre is 100% wrong.

now, back to our period....

[Justin Swanton]

You've resurrected my interest in Napoleonics, Mark. 

But how did Napoleon encamp his corps once they combined? His men had to eat and sleep somewhere before and after the battle.

[Jim Webster]

After the battle you were either defeated and fleeing or victorious and collapsed exhausted on the battlefield so after the battle probably didn't matter too much

Before the battle it seems to vary, but the corps would often camp separately in their own camps are march onto the battlefield separately.
Remember that Napoleonic battles seem to have been fought on big battlefields, Waterloo, which is cramped and unusually small is over two miles across, at Leipzig Napoleon probably had about twenty kilometers of front.

With Napoleonic battles no one reckoned you could deploy 200,000 men on the same frontage as 20,000 to pack them in

Jim

[Erpingham]

I think one needs to be careful on the space available on the battlefield question.  We frequently don't know in detail the extent or even the precise location of many of them, so saying the front must have been so wide or the depth could have been so many deep may not be too helpful.  It is also true that, certainly in the Middle Ages, armies tended to draw up in lines with gaps between, rather than in solid blocks of great depth, which may also throw off any calculations.  I also recall those Roman chaps went for this method

[Mark G]

napoleon didn't.  the marshals of each corps did.  Napoleon just told them where he wanted them to be the next day (or week, depending), and the roads he wanted them to use to get there.

Completely different from the way ancient generals worked, where they kept the entire army with them at all times, Napoleon barely even had his guard with him at the outset of many campaigns - but he always strove to know how long each bit would have to fight on its own until the next bit could arrive.

which is why one of the key features of a Napoleonic battle is a force arriving part way through from some direction of another.  You can count the number of times that happens in the ancient world on one hand, I recon.