the reign of Justinian, they acknowledged the god and the emperor of the Romans, and seven fortresses were built in the most accessible passages, to exclude the ambition of the Persian monarch. 130 The principal source of the Euphrates descends from the Chalybian mountains, and seems to flow towards the west and the Euxine: bending to the south-west, the river passes under the walls of Satala and Melitene (which were restored by Justinian as the bulwarks of the Lesser Armenia,) and gradually approaches the Mediterranean Sea; till at length, repelled by Mount Taurus, 131 the Euphrates inclines its long and flexible course to the south-east and the Gulf of Persia. Among the Roman cities beyond the Euphrates, we distinguish two recent foundations, which were named from Theodosius, and the relics of the martyrs; and two capitals, Amida and Edessa, which are celebrated in the history of every age. Their strength was proportioned by Justinian to the danger of their situation. A ditch and palisade might be sufficient to resist the artless force of the cavalry of Scythia; but more elaborate works were required to sustain a regular siege against the arms and treasures of the great king. His skilful engineers understood the methods of conducting deep mines, and of raising platforms to the level of the rampart: he shook the strongest battlements with his military engines, and sometimes advanced to the assault with a line of movable turrets on the backs of elephants. In the great cities of the East, the disadvantage of space, perhaps of position, was compensated by the zeal of the people, who seconded the garrison in the defence of their country and religion; and the fabulous promise of the Son of God, that Edessa should never be taken, filled the citizens with valiant confidence, and chilled the besiegers with doubt and dismay. 132 The subordinate towns of Armenia and Mesopotamia were diligently strengthened, and the posts which appeared to have any command of ground or water were occupied by numerous forts, substantially built of stone, or more hastily erected with the obvious materials of earth and brick. The eye of Justinian investigated every spot; and his cruel precautions might attract the war into some lonely vale, whose peaceful natives, connected by trade and marriage, were ignorant of national discord and the quarrels of princes. Westward of the Euphrates, a sandy desert extends above six hundred miles to the Red Sea. Nature had interposed a vacant solitude between the ambition of two rival empires; the Arabians, till Mahomet arose, were formidable only as robbers; and in the proud security of peace the fortifications of Syria were neglected on the most vulnerable side.