[1] But meanwhile the restless Persian was surrounding the city with sheds and mantlets, and mounds began to be raised and towers were constructed; these last were lofty, with ironclad fronts, and on the top of each a ballista was placed, for the purpose of driving the defenders from the ramparts; yet not even for a moment did the skirmishing by the slingers and archers slacken.

[2] There were with us two Magnentian legions, recently brought from Gaul (as I have said) ¹ and composed of brave, active men, experienced in battle in the open field, but to the sort of warfare to which we were constrained they were not merely unsuited, but actually a great hindrance; for whereas they were of no help with the artillery or in the construction of fortifications, they would sometimes make reckless sallies and after fighting with the greatest confidence return with diminished numbers, accomplishing just as much as would the pouring of a single handful of water (as the saying is) upon a general conflagration.

[3] Finally, when the gates were very carefully barred, and their officers forbade them to go forth, they gnashed their teeth like wild beasts. But in the days that followed (as I shall show) their efficiency was conspicuous.

[4] In a remote part of the walls on the southern side, which looks down on the river Tigris, there was a tower rising to a lofty height, beneath which yawned rocks so precipitous that one could not look down without shuddering dizziness. From these rocks subterranean arches had been hollowed out, and skilfully made steps led through the roots of the mountain as far as the plateau on which the city stood, in order that water might be brought secretly from the channel of the river, a device which I have seen in all the fortifications in those regions which border on streams.

[5] Through these dark passages, left unguarded because of their steepness, led by a deserter in the city who had gone over to the opposite side, seventy Persian bowmen from the king’s bodyguard who excelled in skill and bravery, protected by the silence of the remote spot, suddenly one by one in the middle of the night mounted to the third story of the tower and there concealed themselves; in the morning they displayed a cloak of red hue, which was the signal for beginning battle, and when they saw the city surrounded on all sides with the floods of their forces, emptying their quivers, and throwing them at their feet, with a conflagration of shouts and yells they sent their shafts in all directions with the utmost skill. And presently all the Persian forces in dense array attacked the city with far greater fury than before.

[6] We were perplexed and uncertain where first to offer resistance, whether to those who stood above us or to the throng mounting on scaling-ladders and already laying hold of the very battlements; so the work was divided among us and five of the lighter ballistae were moved and placed over against the tower, rapidly pouring forth wooden shafts, which sometimes pierced even two men at a time. Some of the enemy fell, severely wounded; others, through fear of the clanging engines, leaped off headlong and were dashed to pieces.

[7] This being so quickly accomplished and the engines restored to their usual places, with a little greater confidence all ran together to defend the walls.

[8] And since the wicked deed of the deserter increased the soldiers’ wrath, as if they were entering a level ground in a sham fight they used such strength of arm as they hurled their various weapons, that as the day inclined towards noon the enemy were scattered in bitter defeat, and lamenting the death of many of their number, retreated to their tents through fear of wounds.