But here is the greatest of all his mistakes. He tells us that Alexander, on approaching the enemy, made his line eight deep.
It is evident then that now the total length of the line must have been forty stades.
And even if they closed up so that, as described by Homer, they actually jostled each other, still the front must have extended over twenty stades.
But he tells us that there was only a space of less than fourteen stades, and as half of the cavalry were on the left near the sea and half on the right, the room available for the infantry is still further reduced. Add to this that the whole line must have kept at a considerable distance from the mountains so as not to be exposed to attack by those of the enemy who held the foot-hills.
We know that he did as a fact draw up part of his force in a crescent formation to oppose this latter. I omit to reckon here also the ten thousand infantry more than his purpose required.
So the consequence is that the length of the line must have been, according to Callisthenes himself, eleven stades at the most, and in this space thirty-two thousand men must have stood closely packed and thirty deep, whereas he tells us that in the battle they were eight deep.
Now for such mistakes we can admit no excuse.
For when the actual facts show a thing to be impossible we are instantly convinced that it is so.
Thus when a writer gives definitely, as in this case, the distance from man to man, the total area of the ground, and the number of men, he is perfectly inexcusable in making false statements.
Walbank Commentary