Did the Macedonian Phalanx practise othismos with its sarissas?

[PMBardunias]

Let me distill what I am seeing and you can tell me if I have the right of it. 

A) the ochanon can be worn on the upper arm. (With a shield of 60cm or less, you should be able to rotate this to face forward as well as sideways. this works very well in underhand, but also overhand)
B) The ochanon can be worn on the forearm, but in a position that the the elbow can rest on it.

My problem is that I do not see any reason to do both if you you are doing one or the other.  I am all on board with the notion that you can strike overhand with a sarissa, in fact I have shared the videos of Marrozzo's teaching on this. If you are wearing it on the forearm to deploy, why not just swing it around the back or to the side using the telamon?

So, in short, I like the solution you have come up with of both using an ochane and a telamon to support the shield.  My question would be, why would you need to use both at the same time? The pelta is not that heavy, and it spends most of its time held very close to the body, which makes bearing it easy.

One thing I wish you would do so we could end this roundabout discussion is find yourself a sliding door and close it to 45cm. Then stand in said doorway and try the different stances you proffer. From my experience you will rapidly find that you want to turn your body side-on so as to have room to strike. I am larger than the average sarissaphoroi, but not beyond the range of men of the time, see below. I am standing squared forward, then side-on, then trying to squish into 45cm.  Note how much more room you have side on.

As an aside, you can see why a hoplite could not stand at 45cm and actually strike with full range of motion. Anything less than a full range strike loses both power and range.

Lastly, there seems to be a trend toward lengthening the underlayer of ptyruges on Hellenistic armor. Could this have compensated for the higher grip that exposes the thighs?

[Justin Swanton]

Let me distill what I am seeing and you can tell me if I have the right of it. 

A) the ochanon can be worn on the upper arm. (With a shield of 60cm or less, you should be able to rotate this to face forward as well as sideways. this works very well in underhand, but also overhand)

Yes. With the ochanon on the upper arm the shield can be brought to the front of the body, though at an angle, by bringing the upper arm around as much to the front as possible. It's an awkward stance though. I wouldn't try to use the shield defensively like this.

B) The ochanon can be worn on the forearm, but in a position that the the elbow can rest on it.

Yes.

My problem is that I do not see any reason to do both if you you are doing one or the other.  I am all on board with the notion that you can strike overhand with a sarissa, in fact I have shared the videos of Marrozzo's teaching on this. If you are wearing it on the forearm to deploy, why not just swing it around the back or to the side using the telamon?

I tried that. If you pull on the telamon to bring the shield to your side the ochanon tends to slide up to the upper arm anyway. And to keep the shield sideways to the body you have to raise your upper arm to a horizontal position, otherwise the shield just flops around to the front. Keeping in mind you have to retain the grip of your left hand on the sarissa during all this. My pose in the photos above was the only way I could do it.

So, in short, I like the solution you have come up with of both using an ochane and a telamon to support the shield.  My question would be, why would you need to use both at the same time? The pelta is not that heavy, and it spends most of its time held very close to the body, which makes bearing it easy.

Bear in mind that besides the shield the left arm carries the entire weight of the sarissa as it holds it at its centre of balance. But I did also find that without an ochanon it is impossible to brace the shield vertically or horizontally, i.e. so that it does swivel sideways and up-and-done. The telamon makes the shield rigid in both directions. To do this I fastened its two ends to the shield below the level of the ochanon (which works better than fasting it above for some reason).

One thing I wish you would do so we could end this roundabout discussion is find yourself a sliding door and close it to 45cm. Then stand in said doorway and try the different stances you proffer. From my experience you will rapidly find that you want to turn your body side-on so as to have room to strike. I am larger than the average sarissaphoroi, but not beyond the range of men of the time, see below. I am standing squared forward, then side-on, then trying to squish into 45cm.  Note how much more room you have side on.

As an aside, you can see why a hoplite could not stand at 45cm and actually strike with full range of motion. Anything less than a full range strike loses both power and range.

Tried it. A sideways stance does work better for striking. I'm thinking though that if I was pressed from behind in an othis sarissmos crush I would be forced to face forwards, shield braced against my sternum and hip, and right hand brought forward to hold the sarissa next to the left hand, at the sarissa's centre of balance BTW.

Lastly, there seems to be a trend toward lengthening the underlayer of ptyruges on Hellenistic armor. Could this have compensated for the higher grip that exposes the thighs?

Could be.

[PMBardunias]

Tried it. A sideways stance does work better for striking. I'm thinking though that if I was pressed from behind in an othis sarissmos crush I would be forced to face forwards, shield braced against my sternum and hip, and right hand brought forward to hold the sarissa next to the left hand, at the sarissa's centre of balance BTW.

Whew, glad we passed that.  Yes, I agree. In fact it shows something that I try to stress. Othismos is not based on lateral packing, but packing along files. You can get more force per unit width by bringing the files together, but as you surmised there is a point where fouling diminishes your returns.

It is my contention that the 45cm spacing did not exist before sarissaphoroi, created of whole cloth, supposedly inspired by the Illiad, but really a result of the men leading with the left hand and standing side on. I think it was designed to be Un-othismosable, because you cannot close on it.  Are there any records of a phalanx at the 45cm spacing ever being penetrated frontally, as opposed to out fought by other sarissa? So I agree with what you wrote, IF they pushed in some fashion, it happened in the looser order.

[Justin Swanton]

Tried it. A sideways stance does work better for striking. I'm thinking though that if I was pressed from behind in an othis sarissmos crush I would be forced to face forwards, shield braced against my sternum and hip, and right hand brought forward to hold the sarissa next to the left hand, at the sarissa's centre of balance BTW.

Whew, glad we passed that.  Yes, I agree. In fact it shows something that I try to stress. Othismos is not based on lateral packing, but packing along files. You can get more force per unit width by bringing the files together, but as you surmised there is a point where fouling diminishes your returns.

I agree that othismos is about pressure down the length of the file, though your reenactors in Greece had trouble with members of a file popping out sideways until they were braced by two adjacent files. I'm guessing those adjacent files' shields were overlapping the shields of the middle file, i.e. that each file occupied a width of about 60-70cm? My own take is that othismos in a 90cm intermediate order wouldn't work very well since files would be too far apart to brace each other, hence the need for a closer order if there's a proper othismotic push going on.

Given that a sideways or 3/4 stance is best for a strike, it remains that once your sarissa is stuck in your enemy's shield, if the phalanx closes up ranks, pressure from the file will rotate you to a forward facing. So long as you hang on to your sarissa (not difficult in this position) you can contribute to the phalanx's very real forward pressure.

It is my contention that the 45cm spacing did not exist before sarissaphoroi, created of whole cloth, supposedly inspired by the Illiad, but really a result of the men leading with the left hand and standing side on. I think it was designed to be Un-othismosable, because you cannot close on it.  Are there any records of a phalanx at the 45cm spacing ever being penetrated frontally, as opposed to out fought by other sarissa? So I agree with what you wrote, IF they pushed in some fashion, it happened in the looser order.

Actually my contention is that they certainly pushed in close order and maybe in intermediate order, though the latter has problems (see above). I have the impression that the pike phalanx was a development of the hoplite phalanx on all points rather than being something radically new, i.e. it developed every advantageous aspect of the hoplite phalanx whilst minimising the weaknesses.

So shields get smaller partly to allow a 2-handed grip (though that could also be and was achieved with an aspis by moving the ochanon near the top/side of the shield) but also to permit a more packed order which could apply more pressure.

Spears became longer to further extend the reach of the hoplite dory, itself made long to outreach shorter spears of the Archaic period. The longer sarissa overcomes the principal weakness of the hoplite phalanx - the fact a determined and well-protected enemy could get past its spear guard. Holding the sarissa overarm would also follow on naturally from holding the dory overarm.

Files retain the same optimum depth - 8 men - when in close order, which maximises the othismos push for the minimum number of men.

Even the unit of manoeuvre is transposed: the 8x8 Spartan pentekonty becomes the 16x16 syntagma.

I don't know of any cases of phalangite shields being penetrated by pikes, just Roman ones. But enough clear descriptions of a pike phalanx physically driving an enemy back.

[PMBardunias]

I agree that othismos is about pressure down the length of the file, though your reenactors in Greece had trouble with members of a file popping out sideways until they were braced by two adjacent files. I'm guessing those adjacent files' shields were overlapping the shields of the middle file, i.e. that each file occupied a width of about 60-70cm? My own take is that othismos in a 90cm intermediate order wouldn't work very well since files would be too far apart to brace each other, hence the need for a closer order if there's a proper othismotic push going on.

My guess is you have seen Giannis' video. He unfortunately mischaracterized what happened with is edit.  The trial where a man slipped out of file only happened once and it happened because he tried to slam into the man in front of him and careened off sideways.  All of the data we recorded except for one trial was done with men pushing in a single file and there was no problem with slippage.  So no, you don't need a man on each side to keep from falling over. 

This is one of those things that drives me crazy with historians. Why would you "have your own take" having never seen this? It is like me having an opinion on the value of Pi. Since we have done it now many times, why not just ask me or someone who has?  Yes, you can do it in 90cm. Yes it is better in less than 90cm, not so much because the bodies can slide sideways, but because the shields are locked into a solid rank and all movement is coordinated tactilely.  Coordination is everything in othismos. We tried different overlaps. Either around 80+cm with the just the rims overlapped or overlapped to the shoulder of the shield, about 72cm, worked fine. You can get down to about 60cm before you start getting jabbed with the rim of the aspis next to you, which is uncomfortable, or having to turn side-on a bit, which could be deadly because you may not be able to get your aspis in front of your diaphragm again.

Given that a sideways or 3/4 stance is best for a strike, it remains that once your sarissa is stuck in your enemy's shield, if the phalanx closes up ranks, pressure from the file will rotate you to a forward facing. So long as you hang on to your sarissa (not difficult in this position) you can contribute to the phalanx's very real forward pressure.

This is another thing I try to get across to those who have not struck.  You may start with a ¾ stance, but you finish twisted forward.  If not, all you are doing is swaying your arms innefectually with no torso rotation.  This is more important in hoplites where the ¾ stance is seen as an explanation for how to stand at 45cm.  You have to have room to bring the shoulder forward with the strike.

Actually my contention is that they certainly pushed in close order and maybe in intermediate order, though the latter has problems (see above). I have the impression that the pike phalanx was a development of the hoplite phalanx on all points rather than being something radically new, i.e. it developed every advantageous aspect of the hoplite phalanx whilst minimising the weaknesses.

So shields get smaller partly to allow a 2-handed grip (though that could also be and was achieved with an aspis by moving the ochanon near the top/side of the shield) but also to permit a more packed order which could apply more pressure.

I would agree with this most of the way.  I think they were trading a more effective spear fighting for a less effective pushing through the spear shafts. I will try pushing through spears in 2021 at a big get together of hoplites to demonstrate why it is weaker. I learned with hoplite othismos that one demonstration is worth a million words. I also think sarissaphoroi stood side on in synaspismos. If true there can be no true othismos, transmission of force forward in files, but men can still push individually.

Spears became longer to further extend the reach of the hoplite dory, itself made long to outreach shorter spears of the Archaic period. The longer sarissa overcomes the principal weakness of the hoplite phalanx - the fact a determined and well-protected enemy could get past its spear guard. Holding the sarissa overarm would also follow on naturally from holding the dory overarm.

This is very insightful and again I agree most of the way, but when you say an enemy could not get past the spear guard, that is the precondition for othismos in hoplites.  So as I wrote, they trade a better spear hedge for a different, and from what I have seen weaker, othismos.

I did a test at the gym the other day and held a 100lb barbell in a two handed grip, vertically.  Rather quickly fatigue set in and it slipped through my grip. This I could not have held 100lbs pushing through my hands for very long.  Our othismos put out a sustained 800+lbs, with higher instantaneous pulses.  But I think we are agreed that hoplites could not have gone into full othismos when pushing against a spear point that would transfix their aspides.

But, that said, there is a prediction I can make.  If pushing through spears with more than moderate force were a thing, we should see a wrist strap or a bulge ahead of the hand like the balls we see on horseman's lances to keep the lance from slipping back in the grip.

Files retain the same optimum depth - 8 men - when in close order, which maximises the othismos push for the minimum number of men.
Even the unit of manoeuvre is transposed: the 8x8 Spartan pentekonty becomes the 16x16 syntagma.

Just to make sure you don't misunderstand my data.  8 men in files is more of a minimum depth needed for othismos than an optimum depth. Up until 8, men are each adding significant force. 8-12, they are still adding force, but less efficiently.  Over 16 they are adding very little per each additional man- 5-10 lbs each. So optimum would be someplace between 12 and 16 in terms of adding to the forward push, but more ranks help keep you from being pushed back.

In a real world setting, this means that a taxis of 12 ranks can produce more forward thrust than one of 8, but one of 12 is only a bit weaker than one of 16 ranks, and 16 ranks can probably put out comparable forward thrust as any number of ranks give or take 20-30lbs.  Where the benefit of further ranks comes in is by proving a wall-like mass behind your ranks and also in raising the likelihood of random super-high pressure waves.

I think the 4th century Spartan files were 12x3, not 8x8, though of course this could be altered. The Theban/other Greek model looks to have been 8, 16, 24, 48 by not doubling down or by stacking formed taxis of 8 ranks. Perhaps by the 4thc, Sparta was trying to get away with the minimum number of men in file to meet a 16 rank foe.

Check out below.  This is my "skeletal aspis" it has a cut out to show why you cannot use a flat shield to imitate an aspis, but that your arm has to pass through and be on the far side of the wooden disk to be in the right position.  But forget all of that because I am using it like a flat shield here to show you what an aspis sized shield looks like strapped above the elbow.  Note how it covers my body in both orientations. The key is that it has to fit snug, same as on the forearm.  Unlike the forearm though, every time you flex your bicep it holds in on tighter.  I think this could work, while tight telamon just gets in my way.  Again, this is 90cm.  It would work better with a smaller diameter.  Compare the last frame to the Pergamon plaque.

[PMBardunias]

Here is what it would look like on the arm. I have this one handy, but I think there are 3 images that show this.

[Justin Swanton]

This is one of those things that drives me crazy with historians. Why would you "have your own take" having never seen this? It is like me having an opinion on the value of Pi. Since we have done it now many times, why not just ask me or someone who has?  Yes, you can do it in 90cm. Yes it is better in less than 90cm, not so much because the bodies can slide sideways, but because the shields are locked into a solid rank and all movement is coordinated tactilely.  Coordination is everything in othismos. We tried different overlaps. Either around 80+cm with the just the rims overlapped or overlapped to the shoulder of the shield, about 72cm, worked fine. You can get down to about 60cm before you start getting jabbed with the rim of the aspis next to you, which is uncomfortable, or having to turn side-on a bit, which could be deadly because you may not be able to get your aspis in front of your diaphragm again.

Good. I needed to know this. I thoroughly appreciate the need to try these things out. Right now I want about 200 re-enactors, properly kitted out, and formed up in two 10x10 blocks that go at each other in various configurations until we can figure out how this really worked. But until I get that, all I can do is try to visualise and experience it mentally whilst paying attention to numbers. Incidentally I based my take on this passage: 

Average pushing weights are shown on the graph, but the maximum force generated by a single file of ten men was 247 kg (544 lbs). This is surely an underestimate of ancient reality in that a lone file like this must spend some of its energy on maintaining lateral stability and not falling out of line. In the large masses of men within an actual phalanx, files standing alongside would have forced centrally located files into alignment and eliminated their need to expend energy staying in line. And, indeed, when a shorter file of six men pushing against a compression sensor as above was flanked on each side by six man files and all pushed together, mass transferred through the central aspis reached 368 kg (811 lbs).

This is another thing I try to get across to those who have not struck.  You may start with a ¾ stance, but you finish twisted forward.  If not, all you are doing is swaying your arms innefectually with no torso rotation.  This is more important in hoplites where the ¾ stance is seen as an explanation for how to stand at 45cm.  You have to have room to bring the shoulder forward with the strike.

Good. This works with a pike phalanx where the men advance in a 3/4 posture until in striking range. They then strike, shoving their sarissas at each other's shields and ending up facing forwards as you describe, and immediate close ranks for othismos. With files occupying a 48cm wide frontage (or perhaps a bit wider - these measurements are all rather flexible) there shouldn't be any problem.

Actually my contention is that they certainly pushed in close order and maybe in intermediate order, though the latter has problems (see above). I have the impression that the pike phalanx was a development of the hoplite phalanx on all points rather than being something radically new, i.e. it developed every advantageous aspect of the hoplite phalanx whilst minimising the weaknesses.

So shields get smaller partly to allow a 2-handed grip (though that could also be and was achieved with an aspis by moving the ochanon near the top/side of the shield) but also to permit a more packed order which could apply more pressure.

I would agree with this most of the way.  I think they were trading a more effective spear fighting for a less effective pushing through the spear shafts. I will try pushing through spears in 2021 at a big get together of hoplites to demonstrate why it is weaker. I learned with hoplite othismos that one demonstration is worth a million words. I also think sarissaphoroi stood side on in synaspismos. If true there can be no true othismos, transmission of force forward in files, but men can still push individually.

I missed something obvious. In a pike vs. pike pushing match, neither side is going to shove too hard as both sides's shields would end up being pierced and both front ranks killed. A classical application of MAD. Methinks there was a lot of the psychological in this - who's going to push a little harder and risk shields getting pierced and who's going to back off?

Which explains why we read of Roman shields and armour getting pierced - no need for the phalangites to hold back in this case. It doesn't however explain how the Athenians were able to shove the Macedonians back at Chaeronea unless the Macedonian phalanx couldn't generate enough pressure going uphill to penetrate the Athenian shields, but could when it had pulled back and was uphill itself (thus winning the battle).

I did a test at the gym the other day and held a 100lb barbell in a two handed grip, vertically.  Rather quickly fatigue set in and it slipped through my grip. This I could not have held 100lbs pushing through my hands for very long.  Our othismos put out a sustained 800+lbs, with higher instantaneous pulses.  But I think we are agreed that hoplites could not have gone into full othismos when pushing against a spear point that would transfix their aspides.

Try this: lie on a table or something similar so your head and upper shoulders project beyond the table edge and hold the barbell just above your shoulder with your two hands together so it points upwards. The barbell's weight pulls your arms downwards against your chest. See how long you can maintain your grip. This simulates the pressure of the sarissa counteracted by the chaps behind you pushing against your back.

But, that said, there is a prediction I can make.  If pushing through spears with more than moderate force were a thing, we should see a wrist strap or a bulge ahead of the hand like the balls we see on horseman's lances to keep the lance from slipping back in the grip.

We really need to test pike-othismos to see how much pressure is actually generated. A few dead bodies for the cause of Science. 

Files retain the same optimum depth - 8 men - when in close order, which maximises the othismos push for the minimum number of men.
Even the unit of manoeuvre is transposed: the 8x8 Spartan pentekonty becomes the 16x16 syntagma.

Just to make sure you don't misunderstand my data.  8 men in files is more of a minimum depth needed for othismos than an optimum depth. Up until 8, men are each adding significant force. 8-12, they are still adding force, but less efficiently.  Over 16 they are adding very little per each additional man- 5-10 lbs each. So optimum would be someplace between 12 and 16 in terms of adding to the forward push, but more ranks help keep you from being pushed back.

In a real world setting, this means that a taxis of 12 ranks can produce more forward thrust than one of 8, but one of 12 is only a bit weaker than one of 16 ranks, and 16 ranks can probably put out comparable forward thrust as any number of ranks give or take 20-30lbs.  Where the benefit of further ranks comes in is by proving a wall-like mass behind your ranks and also in raising the likelihood of random super-high pressure waves.

I think the 4th century Spartan files were 12x3, not 8x8, though of course this could be altered. The Theban/other Greek model looks to have been 8, 16, 24, 48 by not doubling down or by stacking formed taxis of 8 ranks. Perhaps by the 4thc, Sparta was trying to get away with the minimum number of men in file to meet a 16 rank foe.

8 still seems to be the commonest depth. Why is that if 12-16 is better for othismos?

Check out below.  This is my "skeletal aspis" it has a cut out to show why you cannot use a flat shield to imitate an aspis, but that your arm has to pass through and be on the far side of the wooden disk to be in the right position.  But forget all of that because I am using it like a flat shield here to show you what an aspis sized shield looks like strapped above the elbow.  Note how it covers my body in both orientations. The key is that it has to fit snug, same as on the forearm.  Unlike the forearm though, every time you flex your bicep it holds in on tighter.  I think this could work, while tight telamon just gets in my way.  Again, this is 90cm.  It would work better with a smaller diameter.  Compare the last frame to the Pergamon plaque.

Can you hold a pike vertical at your right side with your left hand whilst keeping the shield at your left side?

[PMBardunias]

 I added two more images.  One that shows the strike motion when side-on.  The other that shows coverage of my 90cm aspis and a virtual 60cm pelta in intermediate sarissaphoroi order and overhand, and how you could push with moderate strength with the shoulder.  As with hoplites, this gets you killed in true othismos, but they could pressumably move to cover the diaphram and stand squared forward.  I think it very possible that sarissaphoroi could find themselves in the old style shield to shield othismos, and this is why they could not lose their shields as other pikemen did.

[PMBardunias]

Good. This works with a pike phalanx where the men advance in a 3/4 posture until in striking range. They then strike, shoving their sarissas at each other's shields and ending up facing forwards as you describe, and immediate close ranks for othismos. With files occupying a 48cm wide frontage (or perhaps a bit wider - these measurements are all rather flexible) there shouldn't be any problem.

Yes, if we move the bar above 45cm, there is no problem 50+ should do it for men with 60cm peltae, but the minimum will be 60 with 60cm pelta if they are very deep because there is no way to overlap very deep rimless shields.


[

I missed something obvious. In a pike vs. pike pushing match, neither side is going to shove too hard as both sides's shields would end up being pierced and both front ranks killed. A classical application of MAD. Methinks there was a lot of the psychological in this - who's going to push a little harder and risk shields getting pierced and who's going to back off?

Yes, this was my point. You do not need true othismos level pressures if you are pushing against a spear point because it is unsurvivable.  But also note that no Roman would enter true othismos unless trapped against a wall or an unyielding mass of men. He would just give ground slowly at some reduced level of pressure. It is very difficult to convey because we are really talking quantitatively rather than qualitatively.  Romans at Zama, Sarissaphoroi in many battles and Hoplites at the end stages of many battles all pushed, but the levels of pressure put out is probably very different just due to survivability and the ability to transfer force in files.

Which explains why we read of Roman shields and armour getting pierced - no need for the phalangites to hold back in this case. It doesn't however explain how the Athenians were able to shove the Macedonians back at Chaeronea unless the Macedonian phalanx couldn't generate enough pressure going uphill to penetrate the Athenian shields, but could when it had pulled back and was uphill itself (thus winning the battle).

If you understand what I wrote above, you will see why it does not matter what the Sarissa do, the Romans would simply give way- as they did. Except the poor Pelignae 
You are assuming that the Athenians faced sarissaphoroi and not hoplites....

Try this: lie on a table or something similar so your head and upper shoulders project beyond the table edge and hold the barbell just above your shoulder with your two hands together so it points upwards. The barbell's weight pulls your arms downwards against your chest. See how long you can maintain your grip. This simulates the pressure of the sarissa counteracted by the chaps behind you pushing against your back.

It was not my arms that gave way, but my grip, so this would make no difference.  In fact it is worse because I cheated at the end as my grip began to fail by tilting the bar and adding more friction by having it at an angle.

We really need to test pike-othismos to see how much pressure is actually generated. A few dead bodies for the cause of Science. 

I will do it with dorys, but the mechanics should be the same.

8 still seems to be the commonest depth. Why is that if 12-16 is better for othismos?

Because, as Epameinondas learned at Mantinea, there is more to combat than othismos.  Remember how the allies tried to limit the Thebans to 16 ranks because since Pagondas, they had been "cheating" and giving themselves an advantage in othismos at the cost of cyclosis for the whole army. So until Pagondas, the accepted trade off seems to be around 8 ranks.  I wonder if the Spartans had started cheating with 12 already, but they were probably able to maximize any depth due to greater coordination, so maybe 12 was a reaction to 16. 16 being a simple stacking or undoubling of files of 8.

Can you hold a pike vertical at your right side with your left hand whilst keeping the shield at your left side?

Yes, not problem. You just rotate it on the bicep.

[Justin Swanton]

You are assuming that the Athenians faced sarissaphoroi and not hoplites....

I am assuming, yes. We can start a thread on the hypaspists' panoply if you like. 

8 still seems to be the commonest depth. Why is that if 12-16 is better for othismos?

Because, as Epameinondas learned at Mantinea, there is more to combat than othismos.  Remember how the allies tried to limit the Thebans to 16 ranks because since Pagondas, they had been "cheating" and giving themselves an advantage in othismos at the cost of cyclosis for the whole army. So until Pagondas, the accepted trade off seems to be around 8 ranks.  I wonder if the Spartans had started cheating with 12 already, but they were probably able to maximize any depth due to greater coordination, so maybe 12 was a reaction to 16. 16 being a simple stacking or undoubling of files of 8.

Which leaves the question: why was 8 ranks the accepted trade off? Why not 12 ranks? What is so special about 8?

[PMBardunias]

I am assuming, yes. We can start a thread on the hypaspists' panoply if you like. 

I'll bet that thread has been done to death, but I think they were hoplites at that date.

Which leaves the question: why was 8 ranks the accepted trade off? Why not 12 ranks? What is so special about 8?

Well, let's look at rank depths.  Minimum depth for a shield wall is 1 rank.  This is good if you are putting up a barrier, such as Sparabara or Spartans besieging long walls. If you have 3 ranks, no amount of ranks cash charge into you and break through immediately. So, three is a good minimum for anyone close-in fighting.  4 is three with a file closer and appears to be the minimum that Hoplites could double down to as Xenophon shows.  5,6, and 7, will outpush 4, but 8 is 4 doubled.  Thus 8 is the next logical jump up from 4 given the way hoplites deploy. 16 is the next, then 24.  Spartans appear to break the system because they deployed in 3 files, not 4, of 6, 9 or 12, but this is tied to the size of enomotia and the age groups called up.

But if you look at the force curve below, you can see there is an inflection at 4 ranks and another at 8, so maybe this is important.  I should note that depth of file adds many not othismos related benefits. Goldsworthy's paper, though ultimately wrong about othismos, demonstrates these well.

[Justin Swanton]

Which leaves the question: why was 8 ranks the accepted trade off? Why not 12 ranks? What is so special about 8?

Well, let's look at rank depths.  Minimum depth for a shield wall is 1 rank.  This is good if you are putting up a barrier, such as Sparabara or Spartans besieging long walls. If you have 3 ranks, no amount of ranks cash charge into you and break through immediately. So, three is a good minimum for anyone close-in fighting.  4 is three with a file closer and appears to be the minimum that Hoplites could double down to as Xenophon shows.  5,6, and 7, will outpush 4, but 8 is 4 doubled.  Thus 8 is the next logical jump up from 4 given the way hoplites deploy. 16 is the next, then 24.  Spartans appear to break the system because they deployed in 3 files, not 4, of 6, 9 or 12, but this is tied to the size of enomotia and the age groups called up.

But did the Spartans habitually deploy 12 deep? They did at Leuctra, (371BC), but they deployed 8 deep at Mantinea (418BC), in Thrace (402BC), at Maeander (399BC) and Corcyra (373BC). They also deployed 9-10 deep at Mantinea (370BC), 2 deep at Thebes (394BC), 4 deep at Athens (408BC) and very deep at Syracuse and Piraeus. It seems that the Spartans were flexible in their depths but overall did prefer 8 ranks. The flexibility may in part be due to the number of their eligible age classes they called up for a particular campaign.

But if you look at the force curve below, you can see there is an inflection at 4 ranks and another at 8, so maybe this is important.  I should note that depth of file adds many not othismos related benefits. Goldsworthy's paper, though ultimately wrong about othismos, demonstrates these well.

My take (sorry! my suggestion) is that the Greeks were very practical about their line depths. A hoplite phalanx was beaten either by being outflanked or outpushed, so they had two things to consider: a) making the line as long as possible in order to outflank their opponent and not be outflanked themselves, and b) making the line deep enough so it could offer a decent othismos. I suspect an 8-deep line would last a reasonable time against a deeper opponent as the pressure difference between 8 and 16 or 50 ranks is much less than between 4 and 8 ranks, enabling one's own longer line to outflank the enemy before the othismos contest was lost. Just a theory.

[PMBardunias]

But did the Spartans habitually deploy 12 deep? They did at Leuctra, (371BC), but they deployed 8 deep at Mantinea (418BC), in Thrace (402BC), at Maeander (399BC) and Corcyra (373BC). They also deployed 9-10 deep at Mantinea (370BC), 2 deep at Thebes (394BC), 4 deep at Athens (408BC) and very deep at Syracuse and Piraeus. It seems that the Spartans were flexible in their depths but overall did prefer 8 ranks. The flexibility may in part be due to the number of their eligible age classes they called up for a particular campaign.

Yes, as I noted the Spartan deployment depended on the number of age groups called up, but depth was always at the discretion of the unit commanders.  This is why I greatly prefer Thucydides's Parataxeis to Xenophon's Phalanx as a description of the hoplite battle line.  Each unit had great independence, from initial deployment to ultimate fate in battle. That said, the treaty before Nemea shows that they were making the calculation you describe, balancing length of line with depth of file.

4 ranks being the smallest shown by Xenophon in his Cilician show, is probably the hoplite minimum of that day and I think probably 3-4 ranks was the early Archaic depth. This was the depth of line that the missile troops of Tyrtaios were shooting over in the same fashion that Persians shot over Spara. Shooting over 8 ranks is a problem. Which is what in my opinion explains the "missile treaty" during the Lelantine war. In this Greek WWI, the great number of troops made deeper ranks necessary for control and resulted in the missile troops behind being ineffective. We don't have depth information for the transition from archaic to classic phalanx- perhaps because until othismos became a common arbiter of battle rather than a thing that happens at the end of some battles, ranks depth was not the sort of thing that needed to be mentioned. So Pagondas comes out of nowhere with 25 ranks.  My guess is that Pritchett is correct that 8 is an urtiefe for hoplites, probably for the reasons we both agree on. But what I do not know is if Athens, Thebans or someone else had been forming at 16 for advantage if they had the numbers to do so before Pagondas.

My take (sorry! my suggestion) is that the Greeks were very practical about their line depths. A hoplite phalanx was beaten either by being outflanked or outpushed, so i.e. they had two things to consider: a) making the line as long as possible in order to outflank their opponent and not be outflanked themselves, and b) making the line deep enough so it could offer a decent othismos. I suspect an 8-deep line would last a reasonable time against a deeper opponent as the pressure difference between 8 and 16 or 50 ranks is much less than between 4 and 8 ranks, enabling one's own longer line to outflank the enemy before the othismos contest was lost. Just a theory.

Ah, here you can have an enlightened opinion. I presented you above with the data from the only othismos study ever done. Thus, you now have as much information about the force curve as I do, and I am very much opened to the way others interpret the data.  Here, as you can see above, I largely agree. There is a clear inflection around 8 men, so this would be a natural depth.
Many, perhaps most hoplite battles did not end in othismos though. One side have way at the initial clash of spears, or after a period of spear fencing. For this phase, my experience suggests only the two font ranks were actively fighting. This is not meant to alter your calculation, because the threat that a battle could go to othismos meant that a) you had to have enough ranks, and b) that you had to be armed with an aspis of round, concave shape.

[Justin Swanton]

Just for interest, here is my hypothetical reconstruction of a phalanx in close order (minus the 4 rear ranks). Front rank presents pikes underarm, other ranks overarm. Each rank alternates in holding the pike on the left and right side (so leaders right, followers left), which minimises the problems of 5 or 6 pikes and their sauroters all close together on one side*, and also means that pikes are no more than about 24cm apart - creating an impenetrable wall. Using my improvised shield I found no problem in holding it with right as well as left arm, with pike at my right and left shoulder, and without changing the ochanon-telamon arrangement.

*just as much a problem for the standard underarm model.

[PMBardunias]

Except it won't work with any peltae that are not nearly flat- hense "not too deep".  See why you cannot overlap deep peltae below; two methods of overlap.  The only way to have a straight line like you show is to have the peltae angled anyway. I am actually not against an angled line, as long as both lines angled obliquely, they still meet even. It also adds the tendency to win on the right, or leading edge, but it would look much different that your image above.  My bigger problem is that overlapping on such a sloped and rimless shields would not be very effective. There is no need to  make too much of overlapping in any case, a shield wall functions fine without it. The main benefit is the tighter physical link between men that makes moving in unison easier.