The First World War was an unprecedented catastrophe that killed millions and set the continent of Europe on the path to further calamity two decades later. But it didn’t come out of nowhere. With the centennial of the outbreak of hostilities coming up in August, Erik Sass will be looking back at the lead-up to the war, when seemingly minor moments of friction accumulated until the situation was ready to explode. He'll be covering those events 100 years after they occurred. This is the 115th installment in the series.
May 1, 1914: French Finalize War Plan with Fatal Flaws
In April 1913, the chief of the French general staff, Joseph Joffre, presented the basic elements of his plan for war with Germany to the Supreme War Council. In its broad outlines, Plan XVII (so-called because it was the seventeenth war plan adopted by the council) envisaged a vigorous offensive by four French armies ranged along the Franco-German frontier, with one army held in reserve for follow-up attacks. The Supreme War Council approved Plan XVII shortly thereafter, and over the next year Joffre fleshed it out with general directives for each of the five armies. On May 1, 1914, the designated commanders received their final orders under Plan XVII.
Furthest south, the French First Army under General Auguste Dubail would strike east from an area straddling the headwaters of the Moselle River, near Epinal, into southern Alsace, one of the “lost provinces” annexed by Germany following its victory over France in 1871. Meanwhile, the Second Army under Noël Édouard de Castelnau, starting around Nancy, would move northeast into Lorraine, the other “lost province,” in the general direction of Sarrebrücke. This thrust would be supported by the Third Army under Pierre Ruffey, heading due east from Verdun towards Metz. Meanwhile the Fourth Army under Fernand de Langle de Cary would be held in reserve west of St. Mihiel as a “masse de manoeuvre,” to be thrown into battle to exploit openings created by the advance of the Second and Third Armies, as Joffre saw fit. Finally the Fifth Army, under General Charles Lanrezac, was left alone in the north to face whatever German forces might advance through Belgium, to be followed by an advance into Luxembourg and maybe even Germany itself.
As this frequently ambiguous wording suggests, Plan XVII was not a detailed plan of campaign, but rather a general scheme for mobilization and concentration that also contemplated some basic opening moves. Joffre, who fully realized that war is unpredictable, intended Plan XVII to be flexible, allowing improvisation to respond to the enemy’s movements. But even in outline this strategy had fatal flaws.
First of all, Joffre—like most other European generals of his day—believed that bold offensives were the key to victory, enshrining relentless all-out attack (offensive à outrance) as a sacred principle; according to this view, troops could overcome any obstacle as long as they were sufficiently imbued with intangible qualities of spirit and will. Thus Plan XVII opened, “Whatever the circumstance, it is the Commander-in-Chief’s intention to advance with all forces united to the attack of the German armies,” and the French infantry regulations adopted on April 20, 1914 declared that French troops would achieve the best results by rushing the enemy and relying on their bayonets for hand-to-hand combat, adding, “the French Army has returned to its old traditions, and no longer recognizes any law in the conduct of operations but that of the offensive.” But the French, along with the rest of Europe, were about to learn that their “law” held no sway on the modern battlefield, where machine guns, barbed wire, rapid-fire rifles, and heavy artillery made mincemeat of men’s valor.
Even worse, Plan XVII assumed that any German attack through Belgium would be confined to the country’s southeast corner, advancing on Sedan in northern France, the scene of the decisive Prussian victory in 1870. This assumption was questioned by Joseph Gallieni, the original commander of the Fifth Army designated to face the Germans in Belgium, who correctly predicted that their invasion would reach much further north and west, passing by Namur and Dinant, allowing them to threaten French forces with a huge envelopment from behind; however Joffre refused to shift the French armies west to face the threat, and Gallieni eventually resigned in protest. Tellingly, Joffre’s first choice to replace Gallieni, General Alexis Hargon, refused to command the Fifth Army on the same grounds.
Charles Lanrezac, who ended up accepting the command, was no more confident in Plan XVII’s strategy of concentration, echoing Gallieni’s suggestion that Fifth Army and at least some other French forces should be deployed further west along the Belgian border to counter a German invasion in depth. Lanrezac also criticized the decision to send Fifth Army into southeast Belgium, noting in a letter to Joffre, “Clearly, once the Fifth Army is committed to an offensive in the direction of Neufchateau it will be unable to parry a German offensive further north.”
Considering his earlier obstinacy towards Gallieni and Hargon, it’s highly unlikely that Joffre would have given Lanrezac’s concerns any hearing, even in peacetime. But by the time he received Lanrezac’s letter, on August 1, 1914, war was upon them and it was too late for revisions anyway. In the weeks that followed Joffre’s stubborn refusal to face the facts—especially evidence of a massive German invasion through northern and central Belgium—would bring France to the brink of disaster.