Boulogne 1804. Napoleon creates the corps. The Napoleonic Battle

At the time of the constitution of the Grande Armée, following the rupture of the Peace of Amiens in 1803, the Emperor sought to reorganize it at his hand. Although the divisional system had proved its worth, it was incomplete, in that it multiplied Napoleon's direct subordinates far too many times...

... He needs groups of divisions, independent, capable, according to precise orders, of quickly and autonomously carrying out the march to the enemy, and able to be regrouped in his hand for the decisive battle. These will be the army corps, whose command is entrusted to the marshals who have just been raised to this dignity: Bernadotte, Marmont, Davout, Soult, Lannes, Ney and Augereau. Napoleon's success was due to his ability to coordinate the three arms (infantry-cavalry-artillery) through the corps, the first complete tactical level for leading the battle. As a result, the divisions, whose function it had been during the wars of the Revolution, by passing under the subordination of corps commanders, were reduced to a level of execution.

Each corps had its own staff (Jomini was Chief of Staff to Ney during the 1813 campaign, after having served on the staff of the Grande Armée).e under Berthier), two or three infantry divisions with their organic artillery, a brigade or a light cavalry division, a corps artillery, an engineer park and elements of the Train.

This reorganization owes much to the adoption of the Gribeauval artillery system, which, with its articulated coupling, can for the first time in theThis reorganization owes much to the adoption of the Gribeauval artillery system, which, with an articulated hitch, can for the first time in history walk at the same pace as the infantry, not to mention the fact that its range has been doubled compared to the system that preceded it.

As for the staffs, even if the first precise details as to their functioning were only written during the Restoration, they already included very modern advances in terms of operation and even method:

• Intelligence (entrusted to the Light Cavalry): already differentiates between the immediate and future enemy, looking for the enemy in contact and in depth.

• The number of troops and their movements are monitored daily by a system that is not without analogy with our "situations of taking up arms" (S.P.A.).

On the other hand, direct combat (there was no indirect combat in the sense that it is understood today), remains in the hands of the Emperor who sees his ground, his units and his enemy and determines himself alone. The notion of decision aid does not exist. Before and during action, Napoleon gave his corps commanders precise orders from which he did not want them to deviate. He reserves for himself the place and time (the space-time framework) of the decisive engagement.

The best example of the flexibility and efficiency of the system is given by the 1805 campaign, during which the Grande Armée, deployed on the coasts of the North Sea, reached the Upper Danube in a very short period of time to concentrate and act grouped at high altitude. the Upper Danube to concentrate and act as a group at Ulm, to the total surprise of the Austrian command, each corps having its own axis along which depots were set up.Each corps had its own axis along which deposits of food and fodder had been set up, and most of the movements were camouflaged from the enemy's view by the Black Forest. Let us judge: the 1st Corps (Bernadotte) came from Hanover, the 2nd (Marmont) from Holland, the 3rd (Davout) from Etaples, the 4th (Soult) and 5th (Lannes) from the camp of Boulogne, the 6th (Ney) and 7th (Augereau) from the West. It was a veritable lante défer lante converging towards the same zone, each corps commander being autonomous. At Napoleon's staff, Berthier had a table drawn up showing the days and times of departure, the routes, the places of supply and the lodgings of each corps. The daily stages are 20 to 30 kilometres long and rest days are planned. The initial movement of this manoeuvre mass of more than one hundred thousand men, completed by the Bessières Guard and Murat's Cavalry Reserve, did not give rise to any incidents.

The system would continue throughout the Empire, but during the Russian campaign, given the vastness of the environment, the army corps lost their autonomy. The Emperor directly commanded his maneuvering mass, 400,000 men out of 600,000, while Eugène de Beau Harnais and Jérôme Bonaparte commanded armies.The level of the army corps was exceeded to reach that of the army.

In 1813, Napoleon returned to the system of autonomous army corps, of which there were 14, which was obviously too many. In 1814, during the French campaign, the Emperor commanded the main (very small) army between the Marne and the Seine, while Eugène, at the head of a Franco-Italian army, defended the border of the Pyrenees.

The special case of the Cavalry Reserve

The Cavalry Reserve is the reunion of a Cavalry Corps...²heavy cavalry (cuirassiers, then carabinieri) and line cavalry (dragons), grouped into divisions of this or that weapon subdivision, directly on the orders of the Emperor who intended it to "create the decision". When the Grande Armée reached the volume of 600,000 men for the campaign of Rus sie, the Cavalry Reserve aligned six cavalry corps. It is very interesting to dwell a little on the Emperor's idea of his job.

For Napoleon, the Cavalry Reserve, in fact, was never to be engaged in the face of an enemy not already taken to task and "shaped" by the army corps, in the initial phase of the battle. Thus, at Austerlitz, Murat was hired to cut off Kutusov's retreat; at Jena, after the Prussian rout, the reserve was hired to cut off Kutusov's retreat; and at Jena, after the Prussian rout, the reserve was hired to cut off Kutusov's retreat.At Jena, after the Prussian rout, the reserve was launched in deep exploitation, as far as beyond Berlin; and at Eylau, the charge known as the "Eighty Squadrons" was aimed at supporting Augereau. The idea that the cavalry could not be engaged in the face of a fresh enemy was lost sight of by Ney at Waterloo, during his charges, as furious as they were desperate, against the entrenched English squares. But above all, in 1870, when the place of the cavalry on the battlefield was already beginning to be strongly questioned by the lessons (unread in France) of the Civil War, the French army superbly ignored this reality. These attitudes led to Woerth's disastrous charges at the Battle of Frœschwiller: to support one of his wing corps, Mac Mahon asked Bonnemains, commanding a cavalry division, to charge the device facing him. Knowing the rules of employment of his regiments, Bonnemains asked Mac Mahon if the enemy that had been designated to him could be subjected to prior artillery preparation. He got this disdainful answer from Mac Mahon: "Since when have my cavalry generals been afraid? "This illustrates Mac Mahon's total carelessness and the accuracy of Bonnemains' views.

The military awakening after 1870. The organization laws of 1872 and 1882.

Until the Franco-Prussian War of 1870, the corps had never been a permanent peacetime structure, except under the Empire. Napoleon III had indeed sketched out a roughly equivalent territorial structure, under the name of "Grand Command", but the project was never completed. Thus, one of the first reorganization measures taken as early as 1872 through legislation was to copy the model of German territorial organization, a military region corresponding to This is why the terms "region" and "corps" are often used interchangeably. The territory was divided into 18 regions and a nineteenth was established in Algiers.³.

As such, the corps is the only complete and homogeneous element, as the army is not a peacetime echelon.⁴...because he's always available:

• of its organs of command;

• of troops;

• services.

All the elements of the corresponding corps were stationed in the territory of the region, namely:

• two infantry divisions (only the Sixth Corps at Châlons had three);
• one light cavalry regiment;

• an artillery regiment;

• elements of the engineers;

• one train squadron.

This system made it possible to re-establish conscription on the basis of local recruitment.

A twentieth Corps was quickly instituted at Nancy, and, at the law of Three Years, a twenty-first at Épinal. The designation of the first regional commanders gave rise to a flood of ambitions, so much so that it was Mac Mahon himself who designated them by name, which makes it possible to find a certain number of great names of the former imperial army.⁵. It is not from above that the intellectual regeneration of the Army will be carried out, but by the Superior War College, created in 1876 and whose first commander was Lewal, who knew how to surround himself with a pleiad of well-made brains. It is significant to note that these regional commanders, directly subordinate to the Minister, were initially given the title of "General Commander-in-Chief".

Among these army corps, a distinction must be made between the so-called "cover corps": These are in fact border corps, which are responsible for moving to the border as soon as they are mobilized, in order to place mobilization and concentration operations outside the threat of a sudden attack by the German enemy.

The corps have a permanent staff in peacetime, and they are even the only level at their disposal. Under the command of a chief of staff, they comprise four offices:

• 1st Office: Personnel, all supplies and health.

• 2nd Office: intelligence, topography.

• Office 3: Operations, Planning and Conduct.

• Office 4: Movement and Transport.

However, as the Command of the Arms, the headquarters (the term used at the time to designate the CP) had some 30 officers, and this figure varied little until 1914.

With regard to the use of the corps, the official documents of the time referred to it as the battle unit. Because of its uniform and invariable composition, it was the only Large Unit that served as the basis for the combinations of the manoeuvre conducted by the High Command.

From a tactical point of view, the divisions are in close dependence on the corps, which intervenes directly in the conduct of their engagement and centralizes its direction entirely.

It was on these organisational and doctrinal bases that the French army entered the campaign in August 1914. These principles, at least of orga nisation, were to evolve very quickly, given the contingency of any battle. Thus, in November 1914, in order to take part in the Battle of Artois, General Pétain was given command of the 33rd A.C., which was newly formed with four divisions. On the other hand, in terms of maneuver, the corps level confirmed that it was the central pivot of the maneuver, designed and conducted at the Army level, which relegated the division to a level of execution.⁶.

2 Initially under the command of Murat.

3 Annex 1 shows the location of the regions/army corps, as well as the names of the first holders of their command.

4 As of 1890, with the creation of the Supreme War Council, the designated commanding generals of the armies will sit on it and will have their chief of staff, but no other officers. They exercise a power of inspection over the corps designated to enter the composition of their armies, according to the planning then in force.

5 It was foreseen that regional commanders would hold their rank, have a command hotel and a military house.

6 Nevertheless, the command of a division is all the more complex because of its very small staff. To illustrate this fact, one need only refer to the chapter in Fayolle's Notebooks, published in 1964, in which he relates his command of the 70th D.I. under Pétain from October 1914 to June 1915, the date on which he succeeded him at the 33rd C.A. One is struck by the difference in the level of concern of Fayolle, who notes his impressions from day to day, without any intention of seeing them published one day, which gives them all their interest. This difference in the level of concern is apparent from the outset, from the very first days. The same observation of the complexity of the command of a division and the difference in level between that of the division and that of the army corps also appears quite clearly in the Correspondence of General Guillaumat, published in 2004.