Helepolis Helepolis ( , English : " Taker of Cities " ) was an ancient siege engine invented by Polyidus of Thessaly and improved by Demetrius I of Macedon and Epimachus of Athens for the unsuccessful siege of Rhodes , based on an earlier , less massive design used against Salamis ( 305 – 304 BC ) . The name was derived from " " ελείν πόλεις " " , meaning " taking " or " capturing cities " , not to be confused with Heliopolis ( Heliou polis ) . Descriptions of it were written by Diodorus Siculus , Vitruvius , Plutarch , and in the Athenaeus Mechanicus . If their numbers are accurate , it was the largest and most powerful siege tower ever erected . Description . The Helepolis was essentially a large tapered tower , with each side about 130 feet ( 41 . 1 m ) high , and 65 feet ( 20 . 6 m ) wide that was manually pushed into battle . It rested on eight wheels , each 15 feet ( 4 . 6 m ) high and also had caster s , to allow lateral movement as well as direct . The three exposed sides were rendered fireproof with iron plates , and stories divided the interior , connected by two broad flights of stairs , one for ascent and one for descent . The machine weighed 160 tons , and required 3 , 400 men working in relays to move it , 200 turning a large capstan driving the wheels via a belt , and the rest pushing from behind . The casters permitted lateral movement , so the entire apparatus could be steered towards the desired attack point , while always keeping the siege engines inside aimed at the walls , and the protective body of the machine directly between the city walls and the men pushing behind it . The Helepolis bore a fearsome complement of heavy armaments , with two 180 - pound ( 82 kg ) catapult s , and one 60 - pounder ( 27 kg ) ( classified by the weight of the projectiles they threw ) on the first floor , three 60 - pounders ( 27 kg ) on the second , and two 30 - pounders ( 14 kg ) on each of the next five floors . Apertures , shielded by mechanically adjustable shutters , lined with skins stuffed with wool and seaweed to render them fireproof , perforated the forward wall of the tower for firing the missile weapons . On each of the top two floors , soldiers could use two light dart throwers to easily clear the walls of defenders . Siege of Rhodes . As the Helepolis was pushed towards the city , the Rhodians managed to dislodge some of the metal plates , and Demetrius ordered it withdrawn from battle to protect it from being burned . Following the failure of the siege , the Helepolis along with the other siege engines were abandoned , and the people of Rhodes melted down their metal plating and sold abandoned weapons using the materials and money to build a statue of their patron god , Helios , the Colossus of Rhodes , known as one of the ancient Seven Wonders of the World . Vitruvius offers an alternative version , in which the Rhodians begged Diognetus , once the town architect of Rhodes , to find a way to capture the Helepolis . By cover of night he had the Rhodians knock a hole through the wall and channel large amounts of water , mud and sewage onto the area where the Helepolis was expected to attack the following day . Diognetus was successful ; the tower was brought forth to the anticipated attack position and became irretrievably stuck in the mire . Once the siege was lifted , the Rhodians sold Demetrius ' abandoned engines and used the money to erect the enormous Colossus of Rhodes . Demetrius also attacked the city with a battering ram long , operated by 1000 men , and he ordered the construction of " korax " , huge drills for boring through walls . Due to his use of siege engines at Rhodes , Demetrius was given the name " Poliorcetes " ( the Besieger ) . In subsequent ages , siege engineers continued to use the name " helepolis " for moving towers which carried battering ram s , as well as machines for throwing spear s and heavy stones . Later usage . Demetrius used his machine again in 292 BC against the Thebans in the capturing Thebes and captured the city the next year . The Byzantines used the term " helepolis " to describe the Traction Trebuchet . The first recorded use of the term was by Theophylact Simocatta in describing the siege of Tiflis in the Byzantine – Sassanid War of 602 – 628 .