Ballista

An ancient heavy missile launcher designed to hurl javelins or heavy balls on the principle of a crossbow. The smaller ballista was just that - a basic, large crossbow fastened to a mount. It was also used to hurl iron shafts, Greek fire, heavy darts, etc. during sieges. The huge, complicated Roman ballista, however, was powered by torsion derived from two thick skeins of twisted cords through which were thrust two separate arms joined at their ends by the cord that propelled the missile. The largest ballistas were quite accurate in hurling 60-pound weights up to about 500 yards. The catapult was yet another machine used for firing bolts and other arrow-like missiles. The two terms are often used interchangeably.

Of the numerous pieces of artillery (possibly about 55) available to the Roman legionary, remarkable were two large torsion engines, the ballista for projecting large boulders, and the catapulta for firing bolts and other arrow-like missiles. A ballista survives at Hatra. The two terms are often used interchangeably.

An ancient heavy missile launcher designed to hurl javelins or heavy balls on the principle of a crossbow. The smaller ballista was just that - a basic, large crossbow fastened to a mount. It was also used to hurl iron shafts, Greek fire, heavy darts, etc. during sieges. The huge, complicated Roman ballista, however, was powered by torsion derived from two thick skeins of twisted cords through which were thrust two separate arms joined at their ends by the cord that propelled the missile. The largest ballistas were quite accurate in hurling 27 kg (60-pound) weights up to about 450 m (500 yards). The catapult was yet another machine used for firing bolts and other arrowlike missiles. The two terms are often used interchangeably. [balista]