The Makedonian phalanx -- why such depth?

[Paullus Scipio]

Coming back to the subject of 'medium' troops I believe their evolution broadly ran thus.......

They first appeared during the Peloponnesian war when Thracian tribal 'peltasts' were hired. They were essentially loose order javelin or longche (dual purpose short spear) armed, but thanks to their shields had a distinct advantage over 'traditional' light troops(psiloi) who were generally servants, shieldless, armed with darts/javelins, or slings or hand-thrown stones, and who undertook the role of skirmishers in 'Hoplite/Phalanx warfare'.

With their shields being 'light' and their shorter spears, loose order and less drill/discipline however, they generally could not stand up to 'heavy' infantry. They were thus 'medium' infantry, and almost invariably 'mercenaries'. Greeks quickly filled this role of 'medium' infantry as well, and down to Alexander's time we hear of both Thracian and Greek 'peltasts', almost always mercenaries.

From time to time , efforts were made to improve the 'hand-to-hand' abilities of peltasts by providing them with swords ( the Thracian Dii tribe used machaira, for example), or thrusting spears ( e.g. Iphicrates 'reforms'), but they were essentially skirmishing troops against heavy/line/phalanx infantry and used for all the traditional light infantry roles, and gradually replaced 'psiloi' except for specialists such as slingers. In places where Hoplite warfare did not 'catch on' ( largely due to lack of poleis/cities) such as Illyria, Thrace, Epirus and Macedonia ( despite it's close ties to Greece) the typical tribal warrior was a peltast. Hoplites did appear in Macedonia, with Greek colonists and poleis/cities, and ultimately 'sarissaphoroi', whom I believe were traditional Macedonian peltasts, armed with 'pelta' and 'longche', but who adopted 'sarissa' and close order drill for pitched battles under Philip.

In the third century BC, following the Gallic invasions, largely defeated by peltasts rather than phalanxes, we see the widescale adoption of the 'thureos'/celtic shield ( even though large oblong shields are known previously among Illyrians and Thracians to a degree) and the city-states adopt 'Thureophoroi' as a combined Hoplite/peltast, but they are not a great success as 'heavy infantry' leading to the adoption of the 'Macedonian manner' for citizen 'heavy infantry', and leaving mercenary 'Thureophoroi' as the replacement for both mercenary hoplites and peltasts ( whom we hear no more of, in their traditional role, in Hellenistic warfare)

The disappearance of the traditional peltast in the hellenistic kingdoms and city-states ( though tribal peltasts still existed) , in turn led to the use of 'peltast/peltophoroi' being used as a term for those troops still carrying 'peltai' - namely professionals/citizen troops armed 'in the Macedonian manner'......
Thus the term 'mistophoroi'/wage-earners/mercenaries comes to mean in a generic sense 'thureophoroi', though there were also specialist mercenaries too, such as Cretan archers or Tarentine cavalry.......

Now I know I have made a number of generalisations here, which can be disputed, but I am simply trying to provide a general background for those readers of the thread not into the minutiae of Hellenistic troop types......