of the ruined wall by directing an incessant storm of arrows into the gap made by the waters.  But the firmness and activity of the garrison and inhabitants defeated this well-imagined proceeding.  While the heavy-armed troops stood in the gap receiving the flights of arrows and defending themselves as they best could, the unarmed multitude raised a new wall in their rear, which, by the morning of the next day, was six feet in height.  This last proof of his enemies’ resolution and resource seems to have finally convinced Sapor of the hopelessness of his enterprise.  Though he still continued the siege for a while, he made no other grand attack, and at length drew off his forces, having lost twenty thousand men before the walls, and wasted a hundred days, or more than three months.

Perhaps he would not have departed so soon, but would have turned the siege into a blockade, and endeavored to starve the garrison into submission, had not alarming tidings reached him from his north-eastern frontier.  Then, as now, the low flat sandy region east of the Caspian was in the possession of nomadic hordes, whose whole life was spent in war and plunder.  The Oxus might be nominally the boundary of the empire in this quarter; but the nomads were really dominant over the entire desert to the foot of the Hyrcanian and Parthian hills.  Petty plundering forays into the fertile region south and east of the desert were no doubt constant, and were not greatly regarded; but from time to time some tribe or chieftain bolder than the rest made a deeper inroad and a more sustained attack than usual, spreading consternation around, and terrifying the court for its safety.  Such an attack seems to have occurred towards the autumn of A.D. 350.  The invading horde is said to have consisted of Massagatae; but we can hardly be mistaken in regarding them as, in the main, of Tatar, or Turkoman blood, akin to the Usbegs and other Turanian tribes which still inhabit the sandy steppe.  Sapor considered the crisis such as to require his own presence; and thus, while civil war summoned one of the two rivals from Mesopotamia to the far West, where he had to contend with the self-styled emperors, Magnentius and Vetranio, the other was called away to the extreme East to repel a Tatar invasion.  A tacit truce was thus established between the great belligerents—­a truce which lasted for seven or eight years.  The unfortunate Mesopotamians, harassed by constant war for above twenty years, had now a breathing-space during which to recover from the ruin and desolation that had overwhelmed them.  Rome and Persia for a time suspended their conflict.  Rivalry, indeed, did not cease; but it was transferred from the battlefield to the cabinet, and the Roman emperor sought and found in diplomatic triumphs a compensation for the ill-success which had attended his efforts in the field.

CHAPTER IX.