The Makedonian phalanx -- why such depth?

[Paullus Scipio]

Paul B. wrote:

There was no single option for the depth of a phalanx. here Xenophon has chosen the shallowest. With the same troops he could have chosen a depth of 8 or 16 depending on the troops they faced. Surely there is no logical problem with Xenophon being able to tell his men not to double down all the way to 4, but to form the 8 rank formation in close order? In another situation he could tell his men to move directly into close order during the 16 rank step. He also could line up whole lochoi along side each other with gaps between them as he might prior to deployment and then not deploy them at all and face the enemy in orthoi lochoi.

...apart from the fact that Xenophon was not a commander on this occasion, nor even a sub-commander, what you say is correct and I would agree. Nevertheless, Xenophon tells us that Clearchus and Menon drew up, not in the shallowest of many depths, but in their 'customary/normal battle order' which perhaps might also be translated as 'normal fighting formation'. This is 'close order' in fours. Xenophon gives full detail of the Drill for this. (Xen Cyropaedia II.3.21) Xenophon (Constitution XI.4) also gives a less detailed account of the drill of a Spartan enomotia (platoon) of 36 forming up in single file, and "threes" (i.e. three files of 12 - the files of Spartans are often described as 12 deep) which then halve into "sixes" ( the enomotia in close order is 6x6 ). That 'open' to 'close' order is referred to here is certain, because we are told "the phalanx becomes thinner or deeper" i.e. the frontage does not expand or contract.

Marathon comes to mind. It would be hard to find a better "test" of depth than marathon where the thinned center is broken through and the deep flanks are victorious.

Just so! Marathon will have taught a lesson indeed to Greeks....don't thin your Phalanx against Asiatics, or it might get broken through ! 'Normal' formations then are what we might expect to see rather than especially 'thinned' ones.......confirming Xenophon, that fighting in 'half-files' of four was 'normal/customary/the Rule'

Not true. 3 deep can resist a "rush" by a small group of men, like a wedge for example, but a crowd can push through a rank of three men. What you are confusing with pushing is "herding", where police beat a crowd into moving away from them.

...there are innumerable videos around of riots etc showing a thin police line successfully resisting the 'shove' of demonstrators much deeper. Significantly, once the parties are armed there is generally no 'shoving' but rather a 'stand-off' distance between the two forces equal to 'weapon's reach' and sparring takes place at this distance.....

I agree with Xenophon's obvious dig at Theban tactics- 100 ranks are too deep. If you read further though, you will see that he admits the enemy will break through his thin line unless the missiles of he rear rankers and the flank attacks of his other troops break them. I don't think so - he goes on to describe how Cyrus will defeat the vast numbers, allowing the "Lydians" to outflank him, will be beaten; you'll have to specify the passage you're referring to...
It runs counter to your arguement that as the 5th/4th centuries progress we see phalanxes becoming generally deeper while concurrently the threat of envelopment is rapidly increasing due to better handling of light troops and cavalry.
I think it is possible to over-simplify here - for example one factor in increasing depth is that the cities fought their wars on the same old battlefields often, but with larger and larger armies, and since the battlefield stayed the same size, larger armies had little choice but to form deeper

Xenophon's take on depth ( the 100 deep of the "Egyptian hoplites") [Xen Cyropaedia VI3.22] is here.....
[22] “And do you think, Cyrus,” said one of the generals, “that drawn up with lines so shallow we shall be a match for so deep a phalanx?”

“When phalanxes are too deep to reach the enemy with weapons,” answered Cyrus, “how do you think they can either hurt their enemy or help their friends? [23] For my part, I would rather have these hoplites who are arranged in columns a hundred deep drawn up ten thousand deep; for in that case we should have very few to fight against. According to the depth that I shall give my line of battle, I think I shall bring the entire line into action and make it everywhere mutually helpful.

You define participate as directly attacking. Participation can be simply adding to morale by standing behind the men who are fighting. Participation can also of cource being there to phisically block their rearward movement- of their own volition or by being driven back by the enemy. The sheer volume of formations deeper than 4 in the history of warfare speak to this benefit.

Agreed - perhaps one should speak of 'active' participation and 'passive' participation.....but you sure as Heck don't need 11/16ths of your force to achieve this effect!! ( morale boosting and physically blocking retreat).

Hence the original question: "The Macedonian Phalanx; Why so deep?"

My answer: On the evidence we have, the best answer is that Greek and Macedonian files, whether 8,12 or 16 deep ( and rarely 10) did not normally fight as files, but rather as half-files, thus the Macedonian phalanx generally would have fought 8 deep, with 5/8 of the soldiers actively participating with their weapons, and 3/8ths passively participating in support.