Following up this first success, the besiegers prepared for an attack upon the wall itself. For this purpose the _helepolis_ was employed. This machine was also called the _ebenhöhe_ because it had to be of even height with the wall. The colossus was made of stout beams and rested upon a base forty feet square. It consisted of three stories. The first was occupied by the men who moved the machine forward on rollers. The second was arranged as a drawbridge, which could be connected with the wall when needed. The uppermost was for use by soldiers, who by means of the drawbridge might drive the enemy from the wall. Like the _tumler_, the _helepolis_ was protected from fire by wet skins.