Close order drill

A military parade is a formation of soldiers whose movement is restricted by close-order manouvering known as drilling or marching. The military parade is now almost entirely ceremonial, though soldiers from time immemorial up until the late 19th century fought in formation. Massed parades may also hold a role for propaganda purposes, being used to exhibit the apparent military strength of one's nation.

The terminology comes from the tradition of close order formation combat, in which soldiers were held in very strict formations as to maximise their combat effectiveness. Formation combat was used as an alternative to mêlée combat, and required strict discipline in the ranks and competent officers. As long as their formations could be maintained, regular troops could maintain a significant advantage over less organised opponents. Military parades are not to be confused with military show of force.

Although the firepower of breechloading rifles and machine guns long ago rendered close formations in battle suicidal, modern armies still use parades for ceremonial purposes or in non-combat environments for their efficiency, ease of organization and encouragement of discipline. Roughly synonymous are "drill" and "march". The English word "drill" is of Middle Dutch origin, dating from the 16th century drill of the Dutch army of prince Maurice of Orange, which was widely copied throughout Europe at the time.

In ancient times, drilling increased in importance when men stopped fighting as individuals and began to fight together as units. Drilling as a vital component of a war machine further increased with the increases in the size of armies, for example when Phillip II of Macedon disciplined his army so they could swiftly form the phalanxes that were so critical to his successes as a general. Military drilling later was used by the Roman Army to maximise efficiency and deadliness throughout their long history. After the fall of the empire, and the Dark Ages set in Europe, most feudal lords more heavily relied on peasant levies and their wealthy knights to fight their wars, the knights for the most part reverting to fighting as individuals. Massed military drilling was used mostly by only the foremost armies and nations, such as the Normans.

...
Wikipedia