After this, though he saw, as I have said before, that many of the towers had after a short time fallen into ruin, yet he was not able to take them down, because the enemy were always close at hand, watching their opportunity, and always trying to find some unprotected part of the fortifications. He therefore devised the following plan: he left these towers where they were, and outside of each of them he constructed another building with great skill, in a quadrangular form, well and securely built. In the same manner he securely protected the ruinous parts of the walls with a second wall. One of these towers, which was called the Watchtower, he seized an opportunity of demolishing, rebuilt it securely, and everywhere removed all fear of want of strength from the walls. He wisely built the outside part of the wall to a sufficient height, in due proportion; outside of it he dug a ditch, not in the way in which men usually make one, but in a small space, and in a different fashion. With what object he did this, I will now explain. The greater part of the walls are inaccessible to besiegers, because they do not stand upon level ground, nor in such a manner as would favour an attack, but upon high precipitous rocks where it would not be possible to undermine them, or to make any assault upon them; but upon the side turned towards the south, the ground, which is soft and earthy and easily dug, renders the city assailable. Here, therefore, he dug a crescent-shaped ditch, deep and wide, and reaching to a considerable distance. Each end of this ditch joined the city wall, and by filling it with water he rendered it altogether impassable to the enemy. On the inner side of it he built a second wall, upon which during a siege the Roman soldiers keep guard, without fear for the walls themselves and for the other outwork which stands before the city. Between the city wall and this outwork, opposite the gate which leads towards Ammodius, there was a great mound, from which the enemy were able to drive mines towards the city unperceived. This he entirely removed, and levelled the spot, so as to put it out of the enemy’s power to assault the place from thence.