He carried out his orders in the following manner. In a place about forty feet distant from the outwork of the city, across the valley in which the river runs between the two mountains, he constructed a barrier of considerable height and width, joining each end of it to the mountain on either side, in such a manner that the water of the river in its strongest flood could never force its way through it. This work is called by those who are learned in such matters a dam, or sluice, or whatever else they please. He did not build this barrier in a straight line, but in the form of a crescent, in order that its arch, which was turned against the stream of the water, might be better able to resist its violence. The upper and lower parts of this barrier are pierced with apertures, so that, when the river suddenly rises in flood, it is forced to stop there and to flow no further with the entire weight of its stream, but passing in small quantities through these apertures it gradually diminishes in violence and power, and the wall is never damaged by it; for the flow of water, collecting in the place which, as I have said before, is about forty feet in length, lying between the barrier and the outwork, is never unmanageable, but runs gently to its usual entrance, and thence is received in the artificial channel. As for the gate, which the fury of the river broke open in former times, he removed it from thence, and blocked up its site with enormous stones, because this gate, being situated on flat ground, was easily reached by the river when in flood; but he placed the gate not far off, in a lofty place in the most precipitous part of the circuit of the walls, which it was impossible for the river to reach. Thus did the Emperor arrange these matters. The inhabitants of this city suffered greatly from the want of water, for there was no fountain springing out of the ground, nor was any water carried about the streets in an aqueduct, or stored up in cisterns; but those who lived in the streets through which the river passed could draw drinking-water from it without trouble, while those who dwelt at a distance from the course of the river had either to fetch their drinking-water with great trouble or to perish with thirst; however, the Emperor Justinian constructed a great aqueduct, by which he brought the water to every part of the city, and relieved the distress of the inhabitants. He also built two churches, that which is called the Great Church, and the Church of St. Bartholomew the Apostle.[37] Moreover, he built very spacious barracks for the soldiers, that they might not inconvenience the inhabitants. Not long after this he restored the wall and outworks of the city of Amida, which had been built in former times, and were thought likely to fall into ruins; thus ensuring the safety of that city. I am now about to speak of his buildings in the forts which stand on the frontier of the territory of these cities.