Ancient army numbers

[Tomenable]

and at Gaugamela indeed 1,000,000.

When we check detailed information from Arrian and Curtius Rufus, we can find the following units / formations / nationalities of the Persian army present at Gaugamela (only in some cases their commanders or their strength is given):

On the left wing of the Persian army:

- 100 scythed chariots
- Scythian horse archers, under Mavaces
- 1000 Bactrian cavalry
- 1000 Dahae cavalry
- 1000 or 2000 (?) Arachotian cavalry, under Barzantes
- (possibly also Indian hillmen with this cavalry, under Barzantes)
- 1000 or 2000 (?) Susian cavalry, under Oxathres
- (possibly also Uxians with Susian cavalry, under Oxathres)
- 2000 Massagetae cavalry, under Satibarzanes
- (possibly some units of infantry of "various nations" added to this cavalry)
- behind them all, 8000 more Bactrian cavalry (possibly includes some Indian cavalry)

- then some unspecified "Persian cavalry and infantry, mixed together"
- possibly also Cadusians (although we see them also on the right wing)

And "This was the arrangement of the left wing as far as the middle of the whole phalanx" (seems a bit far - if the left wing was up to the middle of the whole phalanx - I suppose it is about enemy phalanx -, then where was the center?).

In the center of the Persian line we can see:

- 1000 (?) Grecian mercenary hoplites, under Patron the Phokian (?)
- 1000 kinsmen cavalry with Darius himself
- 1000 apple-bearers guard
- 1000 (?) Grecian mercenary hoplites, under Glaucus the Aetolian (?)
- 15 elephants in front of kinsmen cavalry
- 50 scythed chariots in front of kinsmen cavalry

- Indians (probably different than those hillmen on the left wing)
- Carians
- behind them - Phrygians and Cataonians under their own king
- Mardian archers, probably under Otanes
- Uxians (but previously Arrian writes that Oxathres commanded both Susians & Uxians - so I would suspect they were in one place of the battlefield, but maybe they were split and their cavalry was deployed on left wing, infantry in the center?)
- (possibly also Susians - see above)
- Babylonians
- Persians (I suppose different ones than that mixed infantry-cavalry force on the left), probably under Ariobarzanes
- Sogdianians, probably under Orontobates
- Sitacenians
- "large number of" Caspians under Fradates
- somewhere here, further 50 chariots (but probably non-scythed ones)
- soldiers from Armenia Minor (under Mithraustes or Orontes)
- Belites (?)
- some hillmen from Caspian / Caucasus mountains
- Parthyans (?)

Then on the right wing:

- Parthian cavalry
- Hycarnians (cavalry too I guess)
- Tapurians

All those above under Phrataphernes,

- Sakae cavalry

- Syrians from Coele Syria and mesopotamian Syria (probably 1000 in total)
- Grecian mercenary cavalry (probably 2000 in total)

These Syrians and Grecian mercenaries under Mazaeus,

- Medians
- Albanians
- Sacesinians
- Cadusians (again? - they were already mentioned on the left wing)

All of them under Atropates,

- Cappadocians under Ariaces
- Armenians from Greater Armenia (under Orontes or Mithraustes)

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And that's all they mention.

Although in most case strength of these formations is not given - it doesn't look like there could be 1,000,000 there, contrary to what Arrian writes later.

Curcius Rufus gives 45,000 cavalry (but Arrian gives the number of cavalry as 40,000, on the other hand) and a much more realistic number of infantry than Arrian - 200,000 - which however probably already includes non-combatants (camp servants, etc.), not just actual battle formations.

Macedonian "foot" strength, on the other hand, was most likely more than 40,000 infantry, because I do not think that this number includes non-combatants (and we know they were there - and even "accidentally" took part in the battle, when Macedonian baggage train was charged by Persian & Indian cavalry which had broken through their lines and then headed towards the rather defenceless Macedonian baggage train, surely inflicting heavy losses on camp servants gathered there in the process).