Plan XVII

Plan XVII (pronounced: [plɑ̃ dis.sɛt]) was the name of a "scheme of mobilization and concentration" that was adopted by the French General Staff in 1913, to be put into effect by the French Army in the event of war between France and Germany. Though it was not "a prescribed narrative for the campaign" or battle plan,^[1] the deployment made possible a prompt invasion of Germany and/or Belgium before Germany could mobilise its reserves - one simultaneous to the Russians' invasion of East Prussia.^[2]

Background

Following the defeat of the French armies during the Franco-Prussian War of 1870-71, the French military had to adapt to a new balance of power in Europe. The emergence of the German Empire on the other side of the Rhine, combined with the loss of Alsace and Lorraine, seriously weakened France's strategic position.

In 1898, the French general staff adopted Plan XIV. Taking into account the numerical inferiority of the French Army, Plan XIV was an offensive strategy along the Franco-German border. Besides the increasing disparity in population (by the turn of the century France had a stagnant population of around forty million, compared to fifty million Germans) there was also the problem of reserves. The war of 1870-71 had demonstrated the ability of the German general staff to make use of the German railway network to deploy its armies and its capability to quickly mobilize its reservists into front-line units. While the French general staff began to apply the lessons of the use of railways, the question of using reservists in front-line units was not resolved. Plan XIV did not take reserves into account.

In 1903, Plan XIV gave way to Plan XV. While still defensive in character, Plan XV did consider using reserve formations, although in a subordinate role.

Plan XVI of March 1909 placed greater emphasis on the risk of a German attack through Belgium, and was modified in 1911 by Général Joseph Joffre.^[3]

In 1911, however, an attempt was made by General Victor-Constant Michel, Vice-President of the Conseil supérieur de la guerre and designated supreme commander in case of war, to revert to a defensive doctrine; Michel anticipated a massive assault by the Germans through Belgium, and therefore suggested to counter-attack them rather than go on the offensive immediately. This was rejected by the Minister of War Adolphe Messimy and the other members of the Conseil (among which Joseph Gallieni), also because it called, to defend the whole northwest border, to employ the reserve formations in frontline service.^[4][5] Michel's suggestion was dropped altogether and he was removed.^[6]

Details and justification

Joffre presented Plan XVII in 1913. Unlike other plans, it was a plan to concentrate French forces close to the Franco-German and Franco-Belgian border but did not include a fixed military strategy,^[7] though with the intent of launching a (counter-)offensive into Belgium and/or German Lorraine.^[8]

Plan XVII enacted

When Germany declared war in 1914, France began the execution of Plan XVII with five initiatives, now collectively known as the Battle of the Frontiers:

1. Battle of Mulhouse - (7–10 August 1914)
2. Battle of Lorraine - (14–25 August 1914)
3. Battle of the Ardennes - (21–23 August 1914)
4. Battle of Charleroi - (21- August 1914)
5. Battle of Mons - (23–24 August 1914)

The German deployment plan used in 1914, Aufmarsch II, included a concentration of most German forces (bar 20% to defend Prussia and the German coast) on the German-Belgian border and was used to execute an offensive into Belgium in order to force a Decisive Battle with the French Army.^[9]

Plan XVII was implemented as an offensive into both Alsace-Lorraine and Belgium. The French attack into Alsace-Lorraine resulted in worse losses than anticipated as successful attacks called for far closer artillery-infantry co-operation than French doctrine (despite its embrace of the "spirit of the offensive") provided for. The attacks of the French forces in southern Belgium were conducted with negligible reconnaissance or artillery support and so were repulsed without preventing the German forces' western movement.^[10]

Within a few weeks the French were back in their starting positions, having suffered great losses. Meanwhile, the Germans had advanced against resistance through Belgium and northern France and were just thirty kilometres north-east of Paris. Only the fact that the German attack outran its supply lines, and that Joffre was able to use French rail-lines to move his retreating forces and re-group them behind the river Marne and within 'Fortress Paris' faster than the Germans could pursue, allowed the French and their British allies to reverse the already-faltering German advance with an artillery-heavy French counter-attack in the First Battle of the Marne.^[11]

In 1914 Moltke, Chief of the German General Staff, essentially attempted to apply the offensive strategy of Aufmarsch I (plan for an isolated Franco-German war, allowing 100% of German forces to be deployed against France) to the inadequate western deployment of Aufmarsch II (which allowed only 80%) to counter France's Plan XVII offensive. In the words of the Australian historian Terence Holmes:

Moltke followed the trajectory of the Schlieffen plan [sic], but only up to the point where it was painfully obvious that he would have needed the army of the Schlieffen plan [sic] to proceed any further along these lines. Lacking the strength and support to advance across the lower Seine, his right wing became a positive liability, caught in an exposed position to the east of fortress Paris.^[12]

References

External links

• First World War.com A map of the French and German war plans
• First World War.com French and German war plans
• Terence Holmes explains the inadequate German deployment for August 1914