According to Josephus , the Roman siege towers at Jotapata were 50 feet high and iron-plated to protect them from fire; those at Masada were reported to be 75 feet high. It was possible to have many different devices on siege towers, such as artillery, draw bridges and rams. Those at the top of the tower were to keep defenders off the walls while those below them attempted to breach the wall using ramps. In the battle of Jerusalem in 70 AD the Romans began assault on the third defensive wall within Jerusalem, the tower stood 75ft tall and was compromised when the Jewish resistance tunneled underneath the tower leading it to collapse.  Following a basic design, details of tower construction varied from siege to siege and there is no known treatise which specifies at which level siege equipment should be placed. Vegetius noted that, “besiegers sometimes built a tower with another turret inside it that could suddenly be raised by ropes and pulleys to over-top the wall”.