The multiple bolt crossbow appeared around the late 4th century BC. A passage dated to 320 BC states that it was mounted on a three-wheeled carriage and stationed on the ramparts. The crossbow was drawn using a treadle and shot 10 foot long arrows. Other drawing mechanisms such as winches and oxen were also used. Later on pedal release triggers were also used. Although this weapon was able to discharge multiple bolts, it was at the cost of reduced accuracy since the further the arrow was from the center of the bow string, the more off center its trajectory would be. It had a maximum range of 500 yards.