issus vs gaugamela

[Centurio Nixalsverdrus]

At Issus, Darius led an army that had taken him mere months to assemble. Although they lost, the Persians retreated with the bulk of their better forces (cavalry, immortals, greek mercenaries) intact.

Afaik they lost all their remaining greek troops, correct me if I'm wrong.

After Issus, while Alexander besieged Tyre and Gaza, the Persians (and their allies) counter-attacked on multiple fronts in the Peloponnese, Lydia, the Hellespont and the Aegean. Hardly the actions of an empire on the ropes.
(By sheer bad luck, all of these counter-attacks were defeated).

The actions in the Aegean, and so on the Peloponnesos and the Hellespont were undertaken by the Persian fleet, which was 1) out of supply because of Alexander's strategy of occupying the ports along the Levante, 2) running out of men and ships because the Cyprian / Phoenician contigents sided with Alexander after he had made the local rulers of the area petty kings, 3) without an able leader because Memnon had died. They managed to capture an Aegean city nevertheless.

What was left was the city of Halikarnassos, under Makedonian siege, and uprisings / vain attempts of remaining Persian forces in the more central parts of Asia Minor which have never been under any firm control of the Persians. These attempt can hardly be called ridiculous, but they weren't a big threat either, and were eventually beaten back.

At Gaugamela, the Persians had a better prepared army. They again lost, perhaps more emphatically this time, but they again retreated with a fair number of their better forces intact.

Not only were they perfectly prepared, but even had they prepared the battlefield prior, evening it out for getting the maximum use out of their chariots. But even the best plan never survives the first enemy encounter, and this eventually led to their defeat: they haven't been able to react properly on Alexander's tactical maneuvers. The chariots, for example, resulted mere useless because they were treated by the Makedones much like Carthaginian elephants by Scipio Africanus. Communication lines in the Persian army were not fast enough. Persian troops were (almost) generally inferior to the Makedonians', consisting of general imperial levy, not used to fight on the battlefield as the Makedones were.

After Gaugamela, Darius' resources were certainly more strained than they had been before. But the Persians were still able to fight a decent defensive war, buying time as Darius assembled a new force at Ecbatana. I think it took something like 30 days for Alexander to force his way through the Persian Gates, for example. Obviously, it wasn't exactly ideal having a conqueror traipsing through the heartland of the Persian Empire - but there's every indication that Darius was starting to assemble a decent-sized force at Ecbatana when he was betrayed by Bessus.

Had they listened to Memnon, they would've done exactly this - letting Alexander wander around until he would have to retreat. It didn't correspond to the honour codex of the Achaemenids to do so though, and so Dareius decided to confront the agressor. He lost and fled two times the battlefield (prematurely perhaps). What's a king worth who's on the flight through his empire? I would say that he knew it was over in the moment he fled from Gaugamela.

But if Darius had not been betrayed, the Persian Empire could have fought on. Perhaps they would still have lost. The Macedonian war machine was pretty impressive, and their generals were both talented and experienced.

It wasn't easy to take the rest of the empire after Gaugamela, and I would go as far as to say that it was the most difficult part of the conquest.

So I don't think Issus and Gaugamela were as significant as most textbooks seem to think they are. Great battles, certainly, but they didn't bring about the downfall of the Persian Empire.

I think you are right on the most part, although I'm not so optimistic towards the Persian resistance (and resilience), and especially you neglect a bit the military ability of Alexander the Great and his generals imho.