+17.+ That I may not be thought to detract wantonly from the credit of such great writers, I will mention one battle, which is at once one of the most famous ever fought, and not too remote in point of time; and at which, above everything else, Callisthenes was himself present. I mean the battle between Alexander and Darius in Cilicia. He says that “Alexander had already got through the pass called the Cilician Gates: and that Darius, availing himself of that by the Amanid Gates, made his way with his army into Cilicia; but on learning from the natives that Alexander was on his way into Syria, he followed him; and having arrived at the pass leading to the south, pitched his camp on the bank of the river Pinarus. The width of the ground from the foot of the mountain to the sea was not more than fourteen stades, through which this river ran diagonally. On first issuing from the mountains its banks were broken, but in its course through the level down to the sea it ran between precipitous and steep hills.” Starting with this description of the ground, he goes on to say that “When Alexander’s army faced about, and, retracing its steps, was approaching to attack them, Darius and his officers determined to draw up their whole phalanx on the ground occupied by his encampment, as it then was, and to defend his front by the river, which flowed right along his camp.” But he afterwards says that Darius “stationed his cavalry close to the sea, his mercenaries next along the river, and his peltasts next resting on the mountains.” +18.+ Now it is difficult to understand how he could have drawn up these troops in front of his phalanx, considering that the river ran immediately under the camp:[31] especially as their numbers were so great, amounting, on Callisthenes’s own showing, to thirty thousand cavalry and thirty thousand mercenaries. Now it is easy to calculate how much ground such a force would require. At the most cavalry in a regular engagement is drawn up eight deep, and between each squadron a clear space must be left in the line to enable them to turn or face about. Therefore eight hundred will cover a stade of front; eight thousand, ten stades;[32] three thousand two hundred, four stades; and so eleven thousand two hundred would cover the whole of fourteen stades. If therefore he were to put his whole thirty thousand on the ground, he would have to mass his cavalry alone nearly three times the usual depth; and then what room is left for his large force of mercenaries? None, indeed, unless on the rear of the cavalry. But Callisthenes says this was not the case, but that these latter engaged the Macedonians first. We must therefore understand half the front, that nearest the sea, to have been occupied by the cavalry; the other half, that nearest the mountains, by the mercenaries. We may by these data easily calculate the depth of the cavalry, and the distance the river must have been from the camp to allow of it.