So did Alexander and just about every army before or since. It is just a basic fact that an army marching through your land was at least on par with a plague of locusts, and the locusts wouldn't rape your women and steal your goods. For example, Wellington had to issue very specific orders to ensure his men didn't forage during the peninsular war, it was an accepted part of being in an army.Hannibal lived entirely off the land. He ruined every area he entered,
Don't mistake intelligence for kindness, he was more than capable of being totally ruthless when he wanted to. Alexander was more than intelligent enough to realise that the only way to take and hold the Persian empire was to integrate with it, for example, he 'encouraged' his officers and men to marry local women (something they are on record as hating). It was a masterstroke and a major advance in diplomacy in those times.He was a kind conqueror.
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Anyway, back more on topic - maneuvering of troops. Alexander was facing an idiot in Darius who did not use the basic advantages of the land to weaken Alexander's forces. Even as late as the run up to Guagamela Darius allowed Alexander to cross the Tigris unopposed (the same crossing where the Roman Emporer Julian had serious problems at). Darius also failed to carry out a scorched earth policy (which again caused julian real difficulties), allowing Alexander a leisurely march to the Tigris through very fertile lands. A good defensive general would have stopped Alexander, he would have failed the Wellington test. Hanibal was facing intelligent generals who would have pounced on a mistake.
Alexander's march was still a materpiece of logistics and planning, he went a long way with very few casualties. Hanibal, on the other hand lost 80% of his troops, which is pretty pathetic really. However, Hanibal then proved his worth by maneuvering in a very tight space and surviving, Alexander never had to do that (not to say he wouldn't have been able to, just that he didn't have to).
Genghis did both..........
Another factor against Alexander is the lack of reliable sources (we don't even know how he died). Alexander was a seriously good spin doctor when it came to his own legend. Even the great battles are contentious. For example, at Guagamela the huge dust cloud is only mentioned right at the end (as an excuse for Alexander not capturing Darius), but it must have been there throughout the whole battle. In that case, one of the reasons Alexander may have won is that he could better control a smaller army in poor visibility (particularly one with more professional troops and Captains) than Darius could control his whole unweildy and bloated army.
The control Alexander exerts over his legend is further illustrated by the end of the battle. I've already said that there is strong circumstantial evidence that the commander of Darius' right wing (Mazeus) had had previous contacts with Alexander. The history says that the only reason Alexander couldn't get Darius was that a messenger somehow managed to get from the left flank, through Darius' whole army and find Alexander (all in the middle of a dust cloud that reduced sight to a matter of feet at times) and tell him Parmenion needed his help. Pretty clever messenger to my mind.
An alternative scenario (that also fits the few known facts) is that Alexander couldn't find Darius (not surprising in the dust cloud and also because the masses of retreating persian cavalry in the way). Mazeus had engaged Parmenion but didn't fully commit due to his previous contacts. When Mazeus realised Darius had fled he too pulled back. Alexander, however, needed someone to blame for not getting Darius, and so invented the heroic radar guided messenger and could therefore say he had to rescue Parmenion. He also didn't mention his (to my mind brilliant) contacts with Mazeus as his legend would be lessened if you realise the right wing of Darius' army wasn't fully committed.
Doesn't take away Alexander's overall status, but does make you realise that he fits more closely into myth and legend than many might realise. Hanibal (although a lesser overall General to my mind) and Genghis are at least very well documented by enemies and neutrals, as well as themselves.