OF THE ROMAN EMPIRE.

in the prosecution of the siege, the ardour of ayouthful soldier. After an obstinate combat,the barbarians were repulsed; they incessantlyreturned to the charge; they were again drivenback with a dreadful slaughter; and two rebellegions of Gauls , who had been banished intothe East, signalized their undisciplined courageby a nocturnal sally into the heart of the Per-sian camp. In one of the fiercest of these re-peated assaults, Amida was betrayed by thetreachery of a deserter, who indicated to thebarbarians a secret and neglected staircase,scooped out of the rock that hangs over thestream of the Tigris. Seventy chosen archersof the royal guard ascended in silence to thethird story of a lofty tower which commandedthe precipice; they elevated on high the Per-sian banner, the signal of confidence to the as-sailants, and of dismay to the besieged ; and ifthis devoted band could have maintained theirpost a few minutes longer, the reduction of theplace might have been purchased by the sacri-fice of their lives. After Sapor had tried, with-out success, the efficacy of force and of strata^-gem, he had recourse to ‘the slower but morecertain operations of a regular siege, in the con-duct of which he w r as instructed by the skill ofthe Roman deserters. The trenches were open-ed at a convenient distance, and the troops des-tined for that service advanced, under the port-able cover of strong hurdles, to fill up the ditch,and undermine the foundations of the walls.Wooden towers were at the same time con-structed, and moved forward on wheels, till

207

CHAP.

XIX.