The Makedonian phalanx -- why such depth?

[Paralus]

...I'm afraid your recollection is incorrect, but then no-one can be expected to remember every piece of minutiae about Alexander or his army - not even such a prominent member of the "Pothos" forum as yourself !
In fact we do hear of dekadarchs(file leaders), dimoiritai(double pay men) and two dekastateroi ( ten-stater men) (Arrian Anabasis 7.23) where the incorporation of Persians into the Phalanx is being described.

One needs to be careful in extrapolating information from Alexander's "mixed" phalanx.Ditto late tactical manuals. Arrian only denotes the position of "file leader". Nowhere does Arrian state that the "double pay men" or "ten stater" men are half file leaders or officers of any description. Indeed he describes them being paid such due to their valour and that the ten stater man is held as more honoured than the ordinary soldier. He nowhere describes these men as officers of any description - that descriptor is clearly only applied to the file leader. Were either of these an officer - half-file leader as you claim - Arrian would no doubt have stated so. He felt oblidged to identify the file leader why would he omit the half-file leader?

Arrian, when finishing off this description then baldly states: so that in each company there were twelve Persians and four Macedonians, three of whom received higher pay, and the fourth was in command of the company. Again, only one is denated officer status.

Alexander is likely making the best of what he has ergo, limited numbers. The fighting is going to be done by the front ranks and so he places his bravest men in front - men honoured for their bravery not because they are officers. If we are to apply this information as reflecting the Macedonian phalanx prior to making do with Persians then such men occupied the same positions and there is no "half-file" leader.

The "tactical manuals" - idealised treatises - are written with an ideal phalanx in mind - not neccessarily Philip II's or Alexander III's. In the grand tradition of Greek art it quite possible they apply current armament to earlier centuries.

You'll have to be more specific about your Byzantium reference - the city is referred to too many times in Xenophon for me to track down what you are referring to.....

No distractions about "en machen" or "en taxei" as Giannas has clealry explained that.

Anab, 7.22-23:

Then he proceeded to pass along this order himself and bade the others send it on--to ground their arms in battle line. [23] The men acted as their own marshals, and within a short time the hoplites had fallen into line eight deep and the peltasts had got into position on either wing.

I'm afraid that is an old 'canard' that the Spartans wore 'felt caps' at Sphacteria.

Why does Thucydides mention them as not keeping out the arrows? They are translated as felt helemts or "caps".