Strong opinions weakly held: Hydaspes

[Sean Manning]

I have Heckel and Yardley's collection of ancient sources handy, so here are some thoughts. Arrian 5.13.4 gives Porus 30,000 cavalry, 30,000 picked infantry, 300 chariots, and 200 elephants to fight Alexander. Rufus 8.13.6 gives Porus' army across the Hydaspes 85 elephants, 300 chariots, 30,000 infantry, and an unknown number of cavalry. The Metz Epitome gives the same figures (85 elephants, 300 four-horse chariots, more than 30,000 infantry) but has Taxilies tell Alexander them. Again, this is supposed to be Porus' entire field army not the men available to fight Alexander. Arrian tells us that some elephants and men (infantry?) were left to block the rest of Alexander's men from crossing and taking his army in the flank, and some chariots and cavalry were lost when they ran into Alexander's force shortly after it had crossed.

It goes without saying that each of these numbers should be trusted about as much as a North Korean press release. The fact that they are sincere doesn't make them trustworthy. Its amazing that a competent soldier like Arrian didn't realize that if Porus had 30,000 cavalry the following battle account would make no sense. Before the battle he has Alexander rush ahead with his cavalry and light-armed confident that if Porus sends out his cavalry, those troops alone will trounce them. In the battle itself he has the Indians mass all their cavalry on their left to meet a feint with most of Alexander's cavalry, at which point two hipparchies of Companions ride around the Indian line to menace the cavalry in their flank, Alexander charges, and the Indians fleet to take shelter behind their elephants without striking a blow. They come out once or twice to fight but are badly mauled. Unfortunately, the figures for infantry can neither be trusted nor dismissed out of hand.

Arrian says that Alexander crossed the river with almost 6,000 infantry and about 5,000 cavalry and that he was supperior in cavalry. This seems to be an under-estimate, and his list of units which crossed misses out some Thracian akontistai who appear in his acccount and are named by Rufus. Alexander seems to have had the following units:

Cavalry: Three hipparchies of Companions plus the Agema (paper strength of 1500 + 300?), Bactrians, Sogdians, and Scythians (maybe a paper strength of 1,000 each?), about 1,000 Dahae mounted archers

Heavy infantry: All the hypaspists (paper strength of 4,000?), two taxeis of foot companions (Cleitus and Coenus, paper strength of 4,000?)

Light infantry: Thracian peltasts, Agrianes, (Macedonian?) archers under the command of Tauron. Maybe a paper strength of 3,000?

Which you can turn into 5,000 horse and 8,000 foot fairly easily by assuming that a typical unit is 20-30% under strength and that Arrian's 6,000 foot refers only to heavy infantry.

I don't think its impossible that Alexander willingly faced 30,000 Indians with 13,000 of his own men. He believed he was divine, and his veterans were the best in the world at killing people and breaking things. He also had cavalry superiority, so he didn't have to worry about his infantry line being outflanked. I have no idea whether Porus' kingdom was large enough to produce an army of 30,000 though! And our accounts of the battle sound like the Indian army was much smaller.

Interesting that Alexander selects "from the phalanx of infantry" the hypaspists. Given that both Diodorus and Curtius clearly describe the effectiveness of the sariisa in this action....

Unfortunately, Arrian 5.12.2 and 5.16.3 and 5.17.3 refer to the archers, akontistai, and Agrianes as part of the phalanx too. I think your hypastpist pikemen theory could well be right, but I don't think this particular passage affects it.