of attack had therefore to be adopted, or the siege must have been
abandoned. Rome generally took towns by the battering-ram; but the
engines in use were of such heavy construction that they could not be
dragged up an ascent like that upon which Petra stood. Bessas was in
extreme perplexity, when some Hunnic allies, who happened to be in
his camp, suggested a mode of constructing a ram, as effective as the
ordinary one, which should nevertheless be so light that it could be
carried on the shoulders of forty men. Three such machines were quickly
made; and under their blows the wall would soon have given way, had
not the defenders employed against them the terrible agency of fire,
showering upon them from the walls lighted casks of sulphur, bitumen,
and naphtha, which last was known to the Greeks of Colchis as "Medea's
oil." Uncertain of succeeding in this attack, the Roman general
gallantly led a scaling party to another portion of the walls, and,
mounting at the head of his men, attempted to make good his footing on
the battlements. Thrown headlong to the ground, but undeterred by his
fall, he was about to repeat his attempt, when he found it needless.
Almost simultaneously his troops had in two other places penetrated into
the town. One band had obtained an entrance by scaling the rocks in
a place supposed to be inaccessible; a second owed its success to a
combination of accidents. First, it had happened that a gap had shown
itself in the piece of the wall which sank into the Roman mine, and a
violent struggle had ensued between the assailants and defenders at this
place.

Then, while this fight was going on, the fire which the Persians were
using against the Roman battering-rams had been by a shift of wind blown
back upon themselves, and the wooden structure from which they fought
had been ignited, and in a short time entirely consumed, together with
its inmates. At sight of the conflagration, the Persians who stood in
the gap had lost heart, and had allowed the Roman troops to force their
way through it into Petra. Thus fell the great Lazic fortress, after a
resistance which is among the most memorable in history. Of the three
thousand defenders, seven hundred had been killed in the siege; one
thousand and seventy were destroyed in the last assault. Only seven
hundred and thirty were made prisoners; and of these no fewer than seven
hundred and twelve were found to be wounded. The remaining five hundred
threw themsel