7. At this he was greatly enraged, and determined to lay siege to the fort; but the garrison was very resolute to defend it, believing the place to be nearly inaccessible, and that the king, who was advancing with great speed at the head of a large army, would soon arrive to their assistance. 8. And now, the vineæ and everything else required for the siege being prepared, at the second watch, when the night, which happened to be one of very bright moonlight, made everything visible to the defenders on the battlements, suddenly the whole multitude of the garrison formed into one body, threw open the gates and sallied out, and attacking a division of our men who were not expecting them, slew numbers, among whom one tribune was killed as he was endeavouring to repel the attack. 9. And while this was going on, the Persians, having attacked a portion of our men in the same manner as before from the opposite side of the river, slew some and took others prisoners. And our men, in alarm, and because they believed the enemy had come into the field in very superior numbers, behaved at first with but little spirit; but presently, when they recovered their courage, they flew again to arms, and being roused by the sound of the trumpets, they hastened to the charge with threatening cries, upon which the Persians retired to the garrison without further contest. 10. And the emperor, being terribly angry, reduced those of the cavalry who had shown a want of courage when attacked to serve in the infantry, which is a severer service and one of less honour. 11. Then, being very eager to take a castle where he had incurred so much danger, he devoted all his own labour and care to that end, never himself retiring from the front ranks of his men, in order that by fighting in the van he might be an example of gallantry to his soldiers, and might be also sure to see, and therefore able to reward, every gallant action. And when he had exposed himself a long time to imminent danger, the castle, having been assailed by every kind of manoeuvre, weapon, and engine, and by great valour on the part of the besiegers, was at length taken and burnt. 12. After this, in consideration of the great labour of the exploits which they had performed, and which were before them, he granted rest to his army, exhausted with its excessive toil, and distributed among them provisions in abundance. Then a rampart was raised round the camp, with dense rows of palisades, and a deep fosse, as sudden sallies and various formidable manoeuvres were dreaded, since they were very near Ctesiphon. VI. § 1. From this place they advanced to a canal known as Naharmalcha, a name which means "The River of Kings." It was then dry. Long ago Trajan, and after him Severus, had caused the soil to be dug out, and had given great attention to constructing this as a canal of great size, so that, being filled with water from the Euphrates, it might enable vessels to pass into the Tigris.