death, according to the Biblical account. Due to logistics, long-lasting sieges involving a minor force could seldom be maintained. A besieging army, encamped in possibly squalid field conditions and dependent on the countryside and its own supply lines for food, could very well be threatened with the disease and starvation intended for the besieged. To end a siege more rapidly, various methods were developed in ancient and medieval times to counter fortifications, and a large variety of siege engines was developed for use by besieging armies. Ladders could be used to escalade over the defenses. Battering rams and siege hooks could also be used to force through gates or walls, while catapults, ballistae, trebuchets, mangonels, and onagers could be used to launch projectiles to break down a city's fortifications and kill its defenders. A siege tower, a substantial structure built to equal or greater height than the fortification's walls, could allow the attackers to fire down upon the defenders and also advance troops to the wall with less danger than using ladders. In addition to launching projectiles at the fortifications or defenders, it was also quite common to attempt to undermine the fortifications, causing them to collapse. This could be accomplished by digging a tunnel beneath the foundations of the walls, and then deliberately collapsing or exploding the tunnel. This process is known as mining. The defenders could dig counter-tunnels to cut into the attackers' works and collapse them prematurely. Fire was often used as a weapon when dealing with wooden fortifications. The Byzantine Empire used Greek fire, which contained additives that made it hard to extinguish. Combined with a primitive flamethrower, it proved an effective offensive and defensive weapon. Defensive The universal method for defending against siege is the use of fortifications, principally walls and ditches, to supplement natural features. A sufficient supply of food and water was also important to defeat the simplest method of siege warfare: starvation. On occasion, the defenders would drive 'surplus' civilians out to reduce the demands on stored food and water. During the Warring States period in China (481–221 BC), warfare lost its honorable, gentlemen's duty that was found in the previous era of the Spring and Autumn period, and became more practical, competitive, cut-throat, and efficient for gaining victory. The Chinese invention of the hand-held, trigger-mechanism crossbow during this period revolutionized warfare, giving greater emphasis to infantry and cavalry and less to