The Makedonian phalanx -- why such depth?

[Paullus Scipio]

Sean wrote:

I also think that the most natural way to interpret Polybius's phalanx is as 16 ranks deep with 2 cubits per file. No comment on the other sources!

...despite Paralus/Michael expanding the topic, and using secondary sources, it is worth reminding ourselves that we are trying to discuss the depth of the Macedonian phalanx, and originally looking at the evidence of Polybius/Kallisthenes ( the latter an eye-witness), as given in XII.19-22. I don't think there is any need to "interpret" what is said, for it is quite categorical.( see my post March 17):
". For with the proper intervals for marching order a stade, when the men are sixteen deep, will hold sixteen hundred, each man being at a distance of six feet from the next. "

Paralus wrote:

Polybios, like Thucydides, is not free from error.

Agreed -that is not in dispute, but whether he is mistaken about something as fundamental as the depth of a standard military formation is another matter, and I don't believe he is wrong in this instance. He categorically tells us a "16 deep phalanx" is in 'normal'/open formation, each man 6 feet from the next. Elsewhere, (XVIII.28-30) in describing the pro's and cons of the phalanx, he tells us that a "16 deep phalanx", when closed up, is pretty formidable, and that the rear ranks add to the force of the charge, and prevent the front ranks facing about - he does not refer to the exact depth in this paragraph, nor does he need to, because, in my view, his readers would know that a "sixteen deep phalanx" would close up (to 8 deep) before charging.

....just in this battle. Problem is I’m not interpreting anything Polybios has written; I’m simply stating what he has clearly said.

What he clearly states, referring to this battle, is that when standing 16 deep, the men are 6 feet apart ( see above and March 17 post) and that in battle they fought 8 deep

He then goes on to describe what the task of the other eleven phalangites is: the sheer pressure of their bodily weight in the charge and keeping the missiles off with their “serried mass of pikes”.

No he doesn't - there is no reference to 'eleven',( that is an assumption by you) just the ranks beyond five, and this could easily mean the rear three ranks. In fact nowhere does Polybius ( or anyone else for that matter) actually say that the Macedonian phalanx ACTUALLY fought 16 deep.. The only categorical statement is the one I keep referring to, namely that the "sixteen deep phalanx" in 'normal' ( open) formation actually fought eight deep in close order.

Note that the Macedonians were “still” being led on “in close array” - not open order - whilst Darius’s forces are in “distant view”. Evidently, to be "still led" they had been led to this point “in close array”. Distant would not imply under 100 yards as Arrian clearly indicates that they came within range of the darts only after they had been led on in close array and in measured step until, one presumes, the Persians were no longer “distant”.

....There is no need to speculate on what is meant, for Polybius/Callisthenes is quite specific. Having told us that the sixteen deep formation is in open order, he tells us this formation was adopted ( from 32 deep - double phalanx) some 8,000 yards from the Persian front...
"9 From all this it is quite plain that when Alexander made his army sixteen deep the line .......20 After this he says that Alexander led on his army in an extended line, being then at a distance of about forty stades from the enemy.". According to our source, later still :"He tells us that Alexander, on approaching the enemy, made his line eight deep".
Arrian makes no mention of the formation changes, and the 'close array' is simply a modern translators terminology, hence irrelevant.
That same passage is translated thus by De Selincourt in the Penguin edition:

Alexander rode from one end of his line to the other with words of encouragement for all, addressing by name, with proper mention of rank and distinctions, not only the the officers of highest rank, but the commanders of squadrons and companies; even the mercenaries were not forgotten, where any distinction or act of courage called for the mention of a name, and from every throat came the answering shout: "Wait no longer -forward to the assault !"
The Persian army was in full view; still ,however, Alexander moved forward in line at a deliberate pace, for a too-rapid advance might have thrown the line out of dressing and caused a break somewhere; but once within range of missiles....

No 'distant view', no 'close array'. The point is that Arrian does not describe the formation changes at all, and in any event the account of the eye-witness Callisthenes, with it's detailed remarks about depth, is surely to be preferred to that of Arrian writing in the the second century AD, in this instance. This is the more so when this passage is simply a standard 'battlefield speech topos', which may preserve a few accurate details - Curtius' version of the 'battlefield speech' is similar, but not the same. Incidently, Curtius, unlike Arrian, does refer to the changing formations, telling us that:
" The Macedonian army advanced in thirty-two ranks; for the narrow place did not allow the line to be extended more widely.Then the folds of the mountains began to widen and open a greater space, so that not only could the infantry take their usual order, but the cavalry cover their flanks"
"usual order' here most probably means 'normal order' ( i.e. open), and 16 deep. Notice too that he doesn't bother to mention that in battle they were 8 deep.

Changing the subject, slightly, to the enigmatic one of where the Greek mercenaries etc that made up a third of Alexander's Heavy Infantry were, it may be significant that it is often assumed that it is just Greek cavalry that is sent to the left to bolster Parmenion's command, but Arrian actually says Alexander "sent the Peloponesian troops and other Allied divisions round to Parmenio on the left", so it is a distinct possibility that the Greek Hoplites formed the left flank of the whole infantry line...... D