The Makedonian phalanx -- why such depth?

[Paralus]

Sorry? As I have already related, Arrian does indeed use the words Dekadarch, Dimoirites and two Dekastateroi (Arrian Anabasis VII.23).

Please copy me the passage in latinised Greek where Arrian mentions more than the decurion: you evidently have it.

The weight of attack will be borne by the front three saris-bearing ranks. The Persians - armed in traditional fashion - are simply fillers who will loose javellins and arrows and lend weight to the front sarisa bearers.

Again, this is assumption on your part, for Arrian does not say this at all !!

This is quite silly.

It is a logical deduction based on the passage. Please explain to me just what it is you think Persians armed in their "traditional fashion" ("some were archers, while others had javelins furnished with straps") are going to do in this phalanx. Perhaps they were to act as Polybios describes the other eleven file members acting by waving their bows and thonged javelins above the pahalanx? Perhaps sing marching tunes in Farsi?