"This soon rendered every attack of this nature useless and worse, and their efforts were then concentrated upon the several gates which simultaneously were attempted to be broken in, fired, or undermined. But here again, as often as these attempts were renewed, were they defeated, and great destruction made of those engaged in them. The troops approached, as is usual, covered completely, or buried rather, beneath their shields. They were suffered to form directly under the walls, and actually commence their work of destruction, when suddenly from the towers of the gates, and through channels constructed for the purpose in every part of the masonry, torrents of liquid fire were poured upon the iron roof, beneath which the soldiers worked. This at first they endured. The melted substances ran off from the polished surface of the shields, and the stones which were dashed upon them from engines, after rattling and bounding over their heads, rolled harmless to the ground. But there was in reserve a foe which they could not encounter. When it was found that the fiëry streams flowed down the slanting sides of the shell, penetrating scarcely at all through the crevices of the well-joined shields, it was suggested by the ingenious Periander, that there should first be thrown down a quantity of pitch, in a half melted state, by which the whole surface of the roof should be completely covered, and which should then, by a fresh discharge of fire, be set in a blaze, the effect of which must be to heat the shields to such a degree, that they could neither be held, nor the heat beneath endured by the miners. This was immediately resorted to at all the gates, and the success was complete. For no sooner was the cold pitch set on fire and constantly fed by fresh quantities from above, than the heat became insupportable to those below, who suddenly letting go their hold, and breaking away from their compacted form, in hope to escape from the stifling heat, the burning substance then poured in upon them, and vast numbers perished miserably upon the spot, or ran burning, and howling with pain, toward the camp. The slaughter made was very great, and very terrible to behold." Aurelian next encompasses the city with a double ditch and rampart, in the construction of which he is often interrupted by the frequent sallies of the Palmyrenes from the gates. These preparations and their success are thus described: