the army led by Piye, in order to enhance the efficiency of Kushite archers and slingers. After leaving Thebes, Piye's first objective was besieging Ashmunein. Having assembled his army for their lack of success so far, the King then undertook the personal supervision of operations including the erection of a siege tower from which Kushite archers could fire down into the city. The biggest siege towers of antiquity, such as the Helepolis (meaning "The Taker of Cities") of the Siege of Rhodes in 305 BC, could be as high as 40 m and as wide as 20 m. Such large engines would require a rack and pinion to be moved effectively. It was manned by 200 soldiers and was divided into nine stories; the different levels housed various types of catapults and ballistae. Subsequent siege towers down through the centuries often had similar engines. However, large siege towers could be defeated by the defenders by flooding the ground in front of the wall, creating a moat that caused the tower to get bogged in the mud. The siege of Rhodes illustrates the important point that the larger siege towers needed level ground. Many castles and hill-top towns and forts were virtually invulnerable to siege tower attack simply due to topography. Smaller siege towers might be used on top of siege-mounds, made of earth, rubble and timber mounds in order to overtop a defensive wall. The remains of such a siege-ramp at Masada, for example, have survived almost 2,000 years and can still be seen today. On the other hand, almost all the largest cities were on large rivers, or the coast, and so did have part of their circuit wall vulnerable to these towers. Furthermore, the tower for such a target might be prefabricated elsewhere and brought dismantled to the target city by water. In some rare circumstances, such towers were mounted on ships to assault the coastal wall of a city: at the Siege of Cyzicus during the Third Mithridatic War, for example, towers were used in conjunction with more conventional siege weapons. One of the oldest references to the mobile siege tower in Ancient China was a written dialogue primarily discussing naval warfare. In the Chinese Yuejueshu (Lost Records of the State of Yue) written by the later Han Dynasty author Yuan Kang in the year 52 AD, Wu Zixu (526 BC – 484 BC) purportedly discussed different