The Makedonian phalanx -- why such depth?

[Paralus]

Irrelevant to the phalanx depth,i just note that Diodorus' word for the skythed chariots is "tethrippon" which just means four horsed chariot.

Yes: I too noticed that and it gives one an idea of the “gap” the phalangites had to accord the chariots.

Note also the consistent description of the phalangite shield as aspide. Clealry to Diodorus (and the others of our sources) a shield is an aspide is a shield.

Yes,it never meant something more than just shield.

Hence the rediciculous modern reduction of hypaspists to bearers of aspides only. It is far more likely that these were the king’s shield bearers when he was on foot: exactly the job performed by Peucestas (and others) in India. Little - if anything - to do with the thoroughly modern fixation on size means all.