The use of artillery has played a crucial role in military history as it was decisive for winning battles. It has been used when launching an offensive into enemy territory or to defend the conquered ground from an enemy counterattack. In ancient times and the Middle Ages, before the invention of gunpowder and the cannon, armies used a primitive form of artillery, which consisted of arrows, stones, and fire balls thrown by infantry troops the Romans called 'velites', using bows, crossbows, scorpions, slings, etc. Their purpose was to harass the enemy infantry right before the battle, causing casualties.
Today, artillery is used to preliminary softening up the ground to be attacked, to provide fire support (with creeping barrage) for the spearhead units during an offensive, and to discourage and stop and enemy attack through attrition when defending territory. Softening up ground and fire support deter the enemy from observing the advance of any given force, hindering them from using their weapons. This is the reason that not only high explosive and bunker piercing shells are employed during an attack, but also special smoke shells are used to smoke-screen the enemy vision, hiding the directions of the spearhead advance.
The other use of artillery is for cutting or severing the enemy supply lines, although this role has been taken by ground attack aircraft in World War II. During World War I, many thousands of rounds of harassing fire were expended by the British in the last year of this armed conflict. Although it was very expensive but it was worth the cost, because aiming and shooting up the enemy rear areas at night destroyed the German logistics and supply lines and their routes. However, another important artillery task was counter-battery fire, whose purpose was attacking the enemy artillery positions, preventing the enemy from providing their troops with fire support.
In the history of artillery, the gun (cannon) was replaced by the howitzer during World War I. The cannon was employed only in the direct fire mode. They aimed the gun barrel directly at the troops, shooting in a straight line, which was not effective when the enemy hid in foxhole in the ground. Using howitzer and mortars, however, one can shoot shells in a high arc, lob, by adjusting the elevation to a high degree of angulation. So that the rounds fall from above and exploding just before they hit the ground. This was introduced to overcome the infantry trench protection.
Below, Soviet 122-mm howitzers about to provide fire support during a major Russian counteroffensive in 1944.
