The inundation, confined by the mounds of the Persians, which prevented it from running off, pressed with continually increasing force against the defences of the city, till at last the wall, in one part, proved too weak to withstand the tremendous weight which bore upon it, and gave way suddenly for the space of a hundred and fifty feet.

What further damage was done to the town we know not; but a breach was opened through which the Persians at once made ready to pour into the place, regarding it as impossible that so huge a gap should be either repaired or effectually defended.

Sapor took up his position on an artificial eminence, while his troops rushed to the assault.

First of all marched the heavy cavalry, accompanied by the horse-archers; next came the elephants, bearing iron towers upon their backs, and in each tower a number of bowmen; intermixed with the elephants were a certain amount of heavy-armed foot.

It was a strange column with which to attack a breach; and its composition does not say much for Persian siege tactics, which were always poor and ineffective, and which now, as usually, resulted in failure.