Flamethrowers

• The Greeks were known to use flaming arrows from the time of the siege of Rhodes, in 304 B.C. In 424 B.C., accounts reported a flame-throwing weapon used against Delium's wooden walls. The apparatus consisted of a pot of burning sulfur, tar, and charcoal within a hollow wooden tube. The pots themselves were used as weapons, thrown onto the decks of ships to burn ship and sailor alike. Flamethrowers with powdered coal were used against stone walls.
  
  

Caltrops

• Circa 330 B.C., during the time of Alexander the Great, caltrops were invented and used to stop the elephant infantry of the Persian Army. A caltrop consists of four spikes arranged so that three rest on the ground, while the fourth sticks straight in the air. A defending army arranges the caltrops on the battlefield prior to being attacked. When the enemy army arrives, their cavalry, be it elephant or horse, is stopped by the spikes.
  
  

Catapult

• A catapult hurls arrows, stone or other objects. In 399 B.C., such a device was invented by Dionysius the Elder of Syracuse, but it was perfected by the Greeks into an effective weapon. They created a single-armed machine for projecting large objects, as well as a double-armed machine, or ballista, for firing arrows. The advantage to such a weapon was that a catapult could hurl a 350 pound stone well over 300 feet, making it an invaluable wartime weapon.
  
  

Mines

• Mines were invented and first described in 120 B.C. Unlike the exploding version that comes to mind, these early mines were nothing more than empty earthenware containers. The Greeks buried them in front of the city walls, covered them in grass, and allowed enemy engines and towers to fall into them. A different type of mine was used at sea in the seventh century. A (now lost) formula was put into barrels, lit on fire, and dropped into the ocean. The tide carried it to set fire to enemy vessels.