Little studied and rarely highlighted because it almost always follows a defeat, retirement, if well conducted, paradoxically confers on the leader in charge a great deal of energy and energy.paradoxically confers on the leader in charge a great rite - if not a great glory - because in the art of war, retreat is undoubtedly the most difficult exercise, and few warlords have excelled in it. It is in this respect that this article had its rightful place under the heading "a military thinker".

Military campaigns are best known and studied through their feats of arms, heroic charges, Homeric battles, spectacular victories or lightning offensives. Conversely, the brilliant retreats are little mentioned, probably because of their essentially inconclusive and seemingly unglamorous character. It is true that, at first glance, the words "retreat" and "brilliant" seem antinomic. Thus, for example, the "Russian retreat" has become legendary, not of course for the quality of its conduct or design, but only for its dramatic character. It is however a mistake to conceal the study of retreats because the art of retreat is undoubtedly the most difficult to master for a general, and it is undoubtedly the most discriminating when it comes to questioning the value of a warlord. The general who succeeds in doing so is certainly a great warlord because he is always in a delicate position and most often at the head of defeated and slaughtered forces. Conversely, the winner of an offensive reaps the laurels of glory when, prior to his victory, he usually possessed solid assets over his opponent. Rather than embarking on a necessarily incomplete and questionable evocation of the most beautiful retreats in military history, the study will focus on two of them, different from each other and therefore complementary, in order to draw lessons. In particular, the retreat of Marshal Grouchy at the end of the Belgian campaign of 1815 and the evacuation of Gallipoli in 1915 will be evoked.

What is a retreat?

First of all, it is necessary to define what a retreat is. The concept of "retreat" actually meets two conditions. First, it is a retrograde movement of the totality of the forces engaged in a campaign or at least in a given sector [1]. 1] Moreover, it is a movement of a strategic nature (in the current operative sense), i.e. of great magnitude. Secondly, this movement occurs after a defeat or at least after a failure or in a deadlock situation [2]. 2] In summary, a retreat is not only a movement of an armed force towards its rear; it is a large-scale movement of large and, in principle, defeated forces. 3] It should be noted that this action is very delicate and that it is most often carried out in a state of urgency or even improvisation. As a result, although a movement of this type is generally carried out by routes and towards known and friendly places, this action is one of the most difficult to carry out. Why such a paradox?

A thankless task

In order to understand this, it is necessary to recall a fundamental fact: the vanguard or point of an army[4] is always faster and more mobile in its movements than its rear, composed of logistic convoys, artillery pieces or "stragglers". These constraints can have dramatic consequences in the case of a retreating army because, mechanically, the vanguard of the pursuer moves faster than the rearguard of the pursued army. Aggravating factor, the morale of a retreating army, usually beaten and harassed, is usually failing, which may lead the troop to abandon its equipment and seek to avoid combat. This makes it more difficult to command and coordinate and reduces its operational value. In some cases, non-combatants are added to the columns, which increases the confusion.

As a result, a commander of a retreating army or a leader of a rearguard must choose between two options: either fight to slow down the pace of the enemy's pursuit and risk succumbing, or abandon a large quantity of equipment and prisoners. Thus, the fastest retreats (for example, under the Empire, the French retreats of 1812 and 1813, the Prussian retreat of 1806 or the Austrian retreat of February 1814) are generally the most disastrous. The best generals are therefore those who best succeed in slowing down the enemy's advance with a smaller number of troops, or even a lower morale.

Types of retreat

A quick historical analysis reveals a wide variety of pension types. The most common of these could be described as "earned pensions". The majority of past pensions belong to this category. The army of the defeated retreats in disorder, and it is the pursuer who imposes his rhythm after having taken, in order not to lose him, the ascendancy over his opponent. Let us quote as an example the Prussian retreat of 1806, the French retreat of 1813 [5] or those of the German forces during Operation Bagration of 1944. Conversely, some retreats were followed by furious offensive returns. Among these "retreatsrefused", let us quote in particular those of La Marne in 1914, Marengo in 1800 or Kharkov in 1943. The Second World War also saw the Wehrmacht defeated but not destroyed experimenting with tactics that could be described as "staggered retreats",such as mobile defenses, wear and tear or on successive lines [6]. 6] Some retreats are quite astonishing, such as the "simulated retreat" of Austerlitz, which provokes a pursuit of the opponent, who in reality rushes into the trap.ge tense, or the "negotiated retreats" of the Frencharmies of Egypt and Portugal in 1801 and 1808, armies repatriated with arms, flags and baggage thanks to their opponents' ships. Two other types of retreats deserve to be mentioned and will be studied in greater depth in order to draw lessons from them.

The "controlled retreat", Grouchy 1815

The Napoleonic period, which saw the introduction of the principle of speed and the profusion of campaigns, naturally offers many examples of retreats. However, there are very few masters in this field. Four immediately come to mind: McDonald after the defeat of La Trébie in 1799, the Russian Bagration for his delaying battles of 1805, 1807 and 1812, Clauzel for his remarkable retreat from Spain in 1813, and especially Grouchy for his exemplary retreat of 1815. It is this retreat as little known as the others that will be studied because it brings together almost all the key points.

It is only on June 19, 1815 that Marshal Grouchy is finally warned of the catastrophe at Mont St-Jean. He therefore began a retreat, already compromised, pursued by considerable Prussian forces with a large number of light cavalry. Methodically, the small army of the right wing will retreat foot to foot, in good order, while avoiding adverse overrun movements. Grouchy gave precise orders in order to anticipate the location of the bivouacs; he fixed movement schedules and priority routes for the slowest convoys in order to avoid traffic jams that would only slow down the march. In a second phase, he ensured the coordination of movements between his divisions, and always left a division lightened with its luggage and supported by light cavalry and mounted artillery in order to gain in power and mobility. This rearguard fought several battles. These are sometimes short, with the sole aim of gaining some time, the Prussians deploying at each contact, which delays them, sometimes longer when the terrain (ridge, river, woods, village) favors the defense. Grouchy was thus able to bring all his wounded, logistical convoys and artillery pieces back to French soil, while conducting several delaying battles and without ever suffering heavy losses. He managed to dictate to the enemy the rhythm of his progression while keeping control and cohesion of his troops intact. This little-known retreat confirms that, in this campaign where mistakes and shortcomings multiplied, Grouchy not only fulfilled his mission, but demonstrated the aptitudes of the best army commanders [7].

The great principles of war[8] are beautifully illustrated by these movements: economy of means by the reasoned choice to dedicate part of the forces to combat, either by covering units on the march or by allocating certain routes to certain units; the concentration of efforts by giving a series of well-targeted stop blows on the enemy's vanguard whenever the terrain allows it; finally the freedom of action by dictating to the opponent the pace of the pursuit.

The "hidden retreat", Gallipoli 1915

From February 1915 to January 1916, the Franco-English expeditionary force of the Dardanelles is defeated, losses accumulate and the strait remains Ottoman. This adventure, which cost Sir Winston Churchill, its instigator, his place, therefore logically remained in the collective memory as a great fiasco. However, one particular aspect deserves to be underlined, so remarkable was it: the reembarkation of the troops[9]. 9] If we refer to the definition proposed at the beginning of the article, the word "retreat" is appropriate, since after a military failure, it means the withdrawal of all the forces involved. However, this large-scale evacuation was a model of its kind, a complete success, because it was perfectly planned and then orchestrated.

The key point of the manoeuvre of Lord Hamilton, commander of the expeditionary force, was in fact to conceal the evacuation operations from the adversary by not changing the habits of the front and by organizing diversions. Thus, embarkations took place at night while the artillery continued to pound the Ottoman positions as if to prepare one more offensive. Wounded and heavy equipment were given priority. Infantry fire was triggered, sometimes at a distance, i.e. without any servants, mules loaded with empty crates went up to the front in front of the enemy airmen, troop movements were artificially ordered near the front. In one month, the entire expeditionary force was evacuated [10] in the greatest discretion, the deception being revealed only at the end of the operations. Thus, Lord Hamilton was able to save his means by leaving only a thin curtain of cover, concentrate his efforts by giving priority to logistics, and keep his freedom of action by luring the adversary. From this operation, a sort of inverted "Fortitude"[11], undoubtedly the best historical example of a retreat hidden from the adversary[12], it emerges thata retreat not dictated by urgency must be conducted with an emphasis on planning and the desirable use of a "deception" maneuver.

The Principles

The three main principles of warfare specific to French strategic thinking are therefore perfectly represented in these two retreat models. A fourth principle dear to Marshal Foch, the safety-surprise couple and its negative counterpart, "disappointment", are also well illustrated. Other lessons can be drawn from their study, such as the use of cunning, anticipation (for example, the choice of routes to be taken and bivouac locations) or the use of a mobile, light and aggressive rearguard alternating counter-attacks, stops, fixation points, manoeuvres and stalls in "mutual support". In short, the art of retreating consists of finding the right balance between engagement and refusal to fight.

Less studied and glorified than victories, retreats are therefore rich in lessons because they are more complete in terms of tactical lessons to be learned. Moreover, this art being one of the most difficult, leaders who have excelled in it are among the most deserving, though not often honoured.

1] A retrograde movement executed on the battlefield is qualified as a "withdrawal" or even a "rout" in the precise case where troops in withdrawal are no longer commanded or organized. But the "rout" can also qualify a retreat if the leader who undergoes it no longer has control of his forces.

2] A withdrawal of operational order not carried out under the pressure of the adversary and deliberately chosen, like the one carried out by the German forces in 1917 in Germany in the summer of 1917.vacating the Aisne in order to shorten the front, is probably not a retreat but what should be called a strategic withdrawal (in the current operational sense). The same applies, for example, to the successive withdrawals of the Austrian army during the campaign of 1813 aimed at exhausting the French conscripts in vain marches between Dresden and Prague.

3] Curiously, three of the most dramatic and best-known retreats in French military history are exceptions since they occurred without prior defeat of the main forces, namely the retreat from Russia in 1812, the "debacle" of 1940 and the destruction of the forces of North Tonkin on colonial road 4 in 1950.

4] Composed of light, mobile, eye-catching troops with a high proportion of cavalry and from the 20th century ^mechanized forces.

5] Less known than the retreat of 1812, the end of the German campaign of 1813 is quite comparable to it; thus only 70,000 men crossed the Rhine out of the 450,000 at the beginning of the campaign, figures quite comparable to the 100,000 survivors out of 600,000 of the Russian campaign.

6] Apparently these German operations are more a question of defensive art than of retreat. However, these operations, certainly defensive, are most often part of a general context of German retreat. Moreover, they were not initially part of the doctrine of the Wehrmacht and seem to have been developed from 1943 onwards by force of circumstance. This makes it a new kind of retreat adapted to modern mechanized combat. In addition, they offer good methods to apply in a problem of withdrawal. Three types of defense in depth were in fact implemented by the Reich forces. First, the "mobile defense" made up of halting blows and counter-attacks whose main purpose was to gain time. Then, the "defence of attrition", already experimented by General de Lattre's 14th ID in 1940, which ^{saw the} defender leave in every town, woods and village of the môthe outdated defences, known as "hedgehog defences", in order to stop the enemy offensive and whose goal is mainly attrition and disorganization of the adversary. Finally, the "defence on successive fortified lines" of which the best example is undoubtedly that of the delaying fights of Von Kesselring in Italy in 1944.

7] On the responsibilities of Marshal Grouchy and the other great captains of the 1815 campaign, see the author's article "It is necessary to rehabilitate Grouchy" published in issue 25 of the Cahiers du CESAT in October 2011. The main faults are to be found in particular in Ney, Soult, Drouet d'Erlon and the Emperor himself.

8] Economy of means, concentration of efforts and freedom of action.

9] Examples of successful evacuations by sea include the successful retreats of the Japanese from Guadalcanal or a large part of the German forces from Sicily, both carried out in 1943. That of Dunkirk, on the other hand, cannot serve as a tactical lesson because its success was due mainly to the easing of pressure from German divisions.

10] In one month, from 10 December 1915 to 9 January 1916, 145,000 men, 15,000 animals and 900 artillery pieces were evacuated.

11] It should be remembered that Operation Fortitude, one of the most important "disappointment" actions in history, aimed to make the Allies believe that the German forces would land in the Pas-de-Calais.

12] The battle of La Rothière during the French campaign of 1814 offers another example; the imperial army, however in contact with the coalised nations, escaped during the night by intentionally leaving the bivouac fires on.

An officer of the Army, Commander Fabrice FORQUIN served in particular in the 516th and 511th ^{train regiments}. Holder of a degree in history and passionate about military history, he specialized in particular in the study of the Napoleonic Wars.