Besides these places he also found Hierapolis,[53] which is the chief of all the cities in that region, lying exposed to any enemy that might attack it, but by his own provident foresight he rendered it safe; for, as it originally enclosed a large empty space and on that account the entire circuit of the walls could not be guarded, he cut off the part which was useless, arranged the walls in a safer and more compact form, and, by thus reducing it to the size necessary for use, made it one of the strongest cities of the present day. He also conferred upon it the following benefit. A fountain of sweet water springs perpetually out of the earth in the midst of the city, and forms therein a wide lake; this, indeed, added to the safety of the city when it was beleaguered by an enemy, but in time of peace was by no means necessary, as much water was brought into the city from without. In process of time the inhabitants, having enjoyed a long period of peace, and having never experienced any distress, neglected this spring; for it is not in human nature when in prosperity to make provision against times of adversity; consequently they gradually filled up the lake with rubbish, and were accustomed to bathe in it, to wash their clothes in it, and to throw all kinds of refuse into it.... In this province of Euphratesia were situated two other towns, Zeugma[54] and Neocæsarea, which were indeed towns in name, but were merely surrounded by dry stone walls, built so low that they might be crossed by an enemy without any difficulty, since they could leap over them without fear; while they were so narrow as to be altogether indefensible, because they afforded no room for the garrison to stand upon to defend them; however, the Emperor Justinian surrounded these places also with real walls, of a sufficient width and height, and equipped them with all other means of defence, thus giving them a just right to be termed cities, and rendering them safe from the attacks of the enemy. X. Moreover, with regard to the cities taken from Chosroes, that barbarian, disregarding the perpetual peace which he had sworn to observe, and the money which he had received on account of it, was filled with envy of the Emperor Justinian, because of the conquests which he had made in Libya and in Italy, and considered his plighted faith to be of less importance than the gratification of this passion; he watched his opportunity, when the greater part of the Roman army was away in the West, and invaded the Roman territory unexpectedly, before the Romans had any news of the approach of the enemy; these cities, I say, the Emperor Justinian so strengthened and beautified that they are all at the present time much more flourishing than before, and have no dread of injury from barbarian invasion, fearing no attacks of any kind.