The central challenge to Silva and his battlefield engineers was to overcome the isolated plateau and its fortifications, originally constructed by King Herod. Silva surrounded the mountain fortress by constructing a 6 foot high, 7 mile long siege wall (circumvallation) to prevent attacks and escapes. The wall also enclosed the eight base camps established for the army. After initial efforts to breach Masada's defenses failed, Silva's army built a siege ramp against the western face of the plateau, using thousands of tons of stones and beaten earth. The huge dirt ramp, which survives to this day, allowed the Romans to roll up a battering ram to breach Masada's walls. Silva's victory was incomplete. His opponents, some 960 men, women and children, had committed mass suicide shortly before t