Demetrius (21.1-21.2)

Now, he made war upon the Rhodians[*] because they were allies of Ptolemy, and brought up against their walls his greatest city-taker. Its base was square, and each of its sides measured at the bottom forty-eight cubits. It rose to a height of sixty-six cubits, and tapered from base to summit.

Within, it was divided off into many storeys and chambers, and the side of it which faced the enemy had windows opening out of every storey, and out through these issued missiles of every sort; for it was full of men who fought in every style of fighting. Moreover, it did not totter or lean when it moved, but remained firm and erect on its base, advancing evenly with much noise and great impetus, and this astounded the minds and at the same time greatly charmed the eyes of those who beheld it.