Until the 18th century, the great European powers were all hereditary monarchies. War was not fought from people to people, but from prince to prince, from sovereign to sovereign, in order to establish, strengthen, reinforce or recover dynastic rights. The purpose of war is therefore either the defence of the "pre-square", the monarch's ancestral temporal possession, or the conquest of a city or province which, after annexation, can be used as a pledge in negotiations.

It is generally not a question of destroying a nation, which would have risked upsetting the European balance. Within this strategic framework, if one wishes to describe briefly the fundamental character of warfare in the 18th century, it can be defined as a limited war.

Of course, this character is also the consequence of military techniques which, by giving the defensive a great deal of superiority over the offensive, limited the enterprises of states. Above all, however, it reflects the political conditions of the Europe of the time and is in keeping with the ideas of an aristocratic and classical era in which moderation and moderation are the rule in everything.

In modern times, the advent of individual fire contributed to the rise of the infantry, which was despised as a vulgar piebald.In modern times, the advent of individual fire has contributed to the growth of the infantry, which was scorned as a vulgar piebald in the Middle Ages, leading Montesquieu to say that "the more a nation becomes learned in the military art, the more it acts through its infantry. To improve its power in combat, by increasing the effects of its fire while making it less vulnerable to cannonballs, the old square, the pillar of the deep order, fragmented and eroded.The battalions were lined up in a line next to each other, the cavalry squadrons moved to the wings of this general arrangement, and the whole became a thin line of four ranks, then three.

The front of the armies expands and it becomes impossible for the general to observe all the detailed movements and to command by voice. At the same time, quite empirically during the Bohemian campaign following the abandonment of Prague, which had been recklessly conquered at the beginning of the War of Succession ofIn order to escape the Austrian cavalry in pursuit, Marshal de Broglie divided his army to dilute it in several valleys between Thuringia and the Rhine: it is the birth, with these "army divisions", of the divisional system.

It remains for Guibert to formalize and codify it. Finally, through Gribeauval's choice of light artillery pieces, each infantry battalion could be equipped with two pieces.Then four pieces moved and manoeuvred during the engagement at practically the same rate as the infantry units: The mobile artillery was born and, as Guibert writes, very quickly became the third weapon. It is this triptych of the three weapons, infantry - cavalry - artillery, which dominates the maneuver and tactics of the Revolution to this day. At the same time, Prussia's particular situation had a great influence on its conception of warfare.

Being too small and with few resources, it is difficult for it to endure a long war without danger. Only large structured states like France or Austria can prefer a war of attrition to the hazards of a single major battle: between the War of Devolution in 1668 and the end of the Seven Years' War, the Russian monarch had to fight a war of attrition. 3 In 1763, the France of Louis XIV and Louis XV experienced in one century only rare periods of peace and came out exhausted from these struggles. Prussia, now present on the European scene, has neither the same means, nor the same population, nor the same strategic depth, and runs the risk of rapidly running out of resources. It must therefore seek a decision through battle as soon as possible. 4.

Thus, Frederick II, who asserted that "fire is the destructive element and movement alone is the decisive element", focused all his efforts on the mobility of his army and the power of shock. He increased his maneuvering capacity by using both fixed stores, pre-positioned in large numbers in fortified places, and mobile convoys. He thus gave his army a new freedom of action, the possibility to modify its line of communication and to cover stages of twenty kilometres.

He increased his shock power by prohibiting the charge of the cavalry at walk, trot or fodder, and replacing it with the charge at gallop, in a tight mass and aligned in three rows. Finally, the King of Prussia adopts a new method of combat: the oblique order, which consists of using the linear formation to carry its main effort against a wing of the enemy. Instead of approaching it head-on, where he deploys maximum fire, he attacks it obliquely, after having tried to deceive it by a maneuver.Instead of attacking it head-on, where it deploys maximum fire, it attacks it obliquely, after having tried to deceive it by a diversionary manoeuvre on its main direction of march, so as to overrun it and threaten its communications without dividing itself.

He deploys his army, not parallel to the opponent's front, but obliquely, reinforcing the wing carried forward. The centre of gravity of its forces is thus deployed in front of a wing of the enemy in an extremely favourable local balance of power. This one, fixed by a boarding maneuver, has no time to modify its device to rescue the threatened wing. Frederick II then converged the fire of his infantry and artillery on this wing, while the cavalry, falling back on the enemy's rear, won the decision. It is in this way that at Rossbach he defeated each of his opponents (French of Soubise, Austrians and Russians) separately before they had a chance to regroup.

On the strength of the French experiences that he confronted with the Prussian "model", Guibert, convinced of the primacy of fire, proposed a mixed order: the battalion column for movement, the line for combat. To put an end to the interminable controversies between the thin order and the deep order, a full-scale experiment was carried out by Marshal de Broglie in 1778 at the Vaussieux camp in Normandy, where forty-four infantry battalions, six cavalry regiments and artillery were assembled. This experience confirms that evolution in thin lines is heavy and difficult, that tight columns can move quickly and deploy instantaneously in lines as long as they do not exceed the strength of the battalion.

This is exactly what Guibert had advocated. The corollary is an articulation of regiments and battalions in a ternary mode so that they can move from one device to another by simple and rapid movements. It is now a given that an army can march in several columns and deploy rapidly as soon as its vanguards come into contact. This is a huge advance, as the columns can follow the axes of movement for as long as possible and deploy only on the battlefield. It is no longer possible to refuse combat by covering oneself with the slightest natural obstacle, which until now was enough to stop the progression in lines across the field.

Finally, the last step of the evolution is taken by the articulation of the army in divisions separated by intervals. To maneuver more easily, an army must be split up and the large units thus created are intended to simplify march orders and to facilitate as well as accelerate the movements by which the army can take an order of battle. Ideally, an army should be composed of three or four infantry divisions encompassing 24 battalions and two cavalry wings each forming a division. Marshal de Broglie adopted such an organization for his army as early as 1759, at the same time as he used skirmishers to fight in front of the line and in the intervals. These innovations were ratified by the order of 1788, which organised twenty-one permanent divisions in France, and by the 1776 regulations, which created a company of chasseurs within each line battalion.

Thus, with the application of the measures recommended by Guibert, the voluminous, heavy and often non-permanent armies of the 17th century were replaced by a system of professional armies, sometimes smaller in size but whose leaders favoured manoeuvring and movement. The structures were simplified and homogenized to create inter-service tactical entities capable of moving and manoeuvring autonomously.

The era of battle by mutual consent is over. Considering that it has been going on since the earliest antiquity, one can measure the upheaval that the divisional system brings to the art of warfare. By giving the States, and first and foremost France, the means of increased power, and introduces the notion of total war, which will not cease to grow until the 20th century. This is indeed how Guibert intended it, whose Essay did not confine itself to setting out combat procedures but questioned practically all the practice of warfare up to the 18th century: institutions, methods and doctrines.

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3 War of Devolution, War of Holland, War of the Augsburg League, War of Spanish Succession, War of Polish Succession, War of Austrian Succession and Seven Years War. It was also coming out of the Thirty Years' War into which Richelieu had brought it in in 1635, extended after 1648 by the war against Spain concluded by the Treaty of the Pyrenees in 1659.

4 Thus Prussia emerged absolutely bled dry from the Seven Years' War, and only the sudden disappearance of the Russian monarch in 1762 enabled it to avoid disaster.