The Makedonian phalanx -- why such depth?

[PMBardunias]

Since we know that the way in which the Greeks/Macedonians formed 'close' order was for the rear half of each file to move up beside the front half, thus 'doubling' the number of men on the same frontage and halving the depth,

I don't think we can state that doubling by interposing half files is the way they formed close order. Aelian makes clear that there are various ways of "doubling" in the same space and of extending and contracting the line. The one he describes in the most detail is the moving of alternate men in a file forward and to the side, like shuffling cards- second man in a file becomes the first in a new one.


He also describes the wholesale lateral movement of troops to close up or space out. This appears to have been done at Cynocephale for example: "he ordered the peltasts and heavy armed to double their depth and close up to the right." One of the tacticians described this as halving their frontage and doubling their depth, thus the man on the left end of the line had to hustle right over a long distance! We could argue whether they ended up in close or opened order, but the point is that men were expected to make such gross lateral movements on the field of battle.

Xenophon describes in great detail the doubling you mention, so I have no doubt it is real. But clearly this is more than a means of moving from opened to close order or else you could only double once- then you would be in close order. Note that when he does this fictionally in the Cyropaedia they achieve a final depth of 6 ranks. But in the same time period we have Spartans increasing their depth by countermarching whole units behind allied units on the battlefield.

I don't necessarily believe that because they could double down to 6 or 4 that this means they normally did so. They could simply decide to deploy the 12 or 8 ranks of the prior double in close order, with opened order for the 24 or 16 rank stage, if they had no intention of making their ranks so shallow.

I think clearly there there were many possibilitiesfor how these things were done, but we should also note that rather complex phalanx-like formations can be created without extensive drill. The hoplites of many cities might not have known anything beyond getting into a group with their clan and standing behind or next to certain relatives. Perhaps one reason that only Spartans could fight effectively alongside anyone as we are told.