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The combatants Germany declared war on France on 3 August 1914. Both sides expected a short war. Germany faced the spectre of a two-front war, facing Russia in the east and France and Britain in the west. German strategy was to defeat France in six weeks and then turn its attention to Russia. As envisioned by the
Schlieffen Plan (revised by
Helmuth von Moltke), the Germans embarked on a rapid, circular, counter-clockwise offensive through Belgium and into France with the objective of capturing Paris and enveloping and destroying the French army east of Paris within their six-week timetable. The German violation of Belgium's neutrality brought the
United Kingdom into the war. Britain sent the British Expeditionary Force (BEF) to France. Germany created seven armies for service on the western front. Three of them on the German right flank would be most involved in the Battle of the Marne. At the beginning of the war, the First Army numbered 320,000 men commanded by
Alexander von Kluck; the Second Army had 260,000 men commanded by
Karl von Bülow; and the Third Army commanded by
Max von Hausen had 180,000 men. These numbers would be depleted by the time of the Marne Battle. The French army stationed on the western front initially consisted of five armies of which the Fourth Army, commanded by
Fernand de Langle de Cary, and the Fifth Army, commanded by
Charles Lanrezac, on its left flank would be most involved in the Battle of the Marne. Two additional French armies would be created to stem off the German offensive: the 6th Army commanded by
Joseph Gallieni, created to protect Paris; and the 9th commanded by
Ferdinand Foch. The French armies engaged in the Marne Battle were reinforced by reservists, recruits, and by transfers from other French and colonial armies. French divisions facing the German right wing rose from 17.5 on 23 August to 41 on 6 September, numbering more than 700,000 men. The BEF numbered 130,000 men at the beginning of the war and was commanded by
John French. The Commanders-in-Chief of the armies were a study in contrasts. Moltke, the chief of the German General Staff, remained at his headquarters in
Luxembourg throughout the battle. He issued General Directives by way of emissaries from his headquarters, but gave his army commanders wide latitude in their operations. By contrast, the French commander, Joseph Joffre, was a whirlwind of activity (although insisting on fine dining and an uninterrupted eight hours of sleep every night). Joffre visited his armies and their commanders frequently, driven by a
Grand Prix race car driver. He was ruthless in firing more than 30 French generals who did not meet his standards (or, as some say, who dared to disagree with him). John French, the British commander, was intimidated by the casualties suffered by the British in initial battles and thereafter reluctant to engage the Germans, but finally played an important role in the Battle of the Marne. The strategies of the French and Germans likewise contrasted. The French focused their attention, troops, and defences in eastern France where they believed the Germans would be most dangerous. They were wrong. The Germans mostly stayed on defence in the east, although blunting French attacks. In the east, France had the objective of regaining
Alsace–Lorraine which it had lost to Germany in the
Franco-German war of 1870. The French did not fortify their northwestern border with Belgium as they did not expect the Germans to attack there and also feared being accused of violating Belgian neutrality—and thereby losing British participation in the war. Germany, however, had no compunctions about violating Belgian neutrality as its objective was to win the war quickly before the United Kingdom could intervene decisively. The French and British were outnumbered in contesting the German offensive through Belgium into France. The Germans recognized that a long war was not in their interest as the resources of France, the United Kingdom, and Russia were far greater than their own. To win the war with France quickly would even the odds. To historian Herwig, the Schlieffen Plan, the violation of Belgian neutrality, and the German invasion of France in 1914 were "an all-or-nothing throw of the dice, a high-risk operation born of hubris and bordering on recklessness."
The Great Retreat The Germans and the French had different strategies for what they anticipated would be a short war. France's top priority was to recover Alsace-Lorraine, lost to Germany in the
Franco-Prussian War of 1870. Germany's priority was to defeat France quickly, so that it could turn its attention to the Russians. Both armies at the beginning of the war believed that offence would prevail over defence. The French military philosophy has been characterized as the "cult of the offensive," a belief that
elan (spirit) and
cran (guts) were the essential elements of military victory. The "most terrible August in the history of the world" proved them wrong as artillery and machine guns triumphed over
elan and
cran. A French lieutenant named
Charles de Gaulle said 'that all the courage in the world cannot prevail against gunfire." August 1914 saw bloody battles, nearly all of which the Germans won, the conquest of most of Belgium by Germany, and the rapid advance of the German armies into France. North and west of Paris, the French and British armies retreated before the German onslaught. East of Paris, the French army launched several offensives into Alsace-Lorraine which failed. France's military
Plan XVII anticipated that Germany would concentrate most of its forces in eastern France in Alsace-Lorraine and Joffre clung to that belief, although the commander of the 5th French army,
Charles Lanrezac, repeatedly warned him that the Germans were attacking Belgium in numbers exceeding those of his own and the BEF. Retired general
Joseph Gallieni also warned Joffre that the German's main effort was in the northwest, not the east. On 24 August, Joffre finally acknowledged that his northwestern (left) flank was at risk. He abandoned the aggressive Plan XVII and instead proclaimed that the French armies were "forced to take defensive action...to wear down the enemy's strength and resume the offense in due course." The
Great Retreat began in which the French 3rd, 4th, and 5th armies and the BEF on the French left began a retreat, mostly walking rather than fighting. The French were followed by the German 1st (Kluck), 2nd (Bülow), and 3rd (Hausen) armies. Hundreds of thousands of German, French, and British soldiers marched southeast in summer heat, wearing woollen uniforms and carrying packs, the Germans motivated by the belief that they would soon capture Paris and end the war. German commanders exulted in their victories, but Chief of General Staff Moltke was worried. The Germans were capturing few prisoners and arms, an indication that the French and British were retreating in good order, not in panic. During the retreat, Joffre bolstered his defences. He created two new armies. The 6th was to defend Paris with Gallieni as the Military Governor and
Michel-Joseph Maunoury as the commander of the 6th army. Gallieni demanded not only garrison troops but also a mobile force to confront the advancing Germans. The 9th army headed by
Ferdinand Foch was stationed between the third and fourth French armies. Utilizing the extensive French railway system, Joffre transferred men from the two eastern armies (the 1st and 2nd) to the Marne and integrated semi-trained French reserves into his defence. Meanwhile, the attacking Germans had outrun their logistics and attrition among its soldiers was high. Kluck's first army had advanced beyond the railhead which supplied it. Sixty per cent of its motor transport had broken down as had fodder wagons carrying hay for horses. Its men had marched since leaving Germany one month earlier, fought several battles, and suffered 20,000 men killed, wounded, and ill. The soldiers were "like living scarecrows." With every mile marched southward, the Germans were more isolated from the sources of their supplies while the French were closer to theirs. Demands for more soldiers on other fronts in the war (and possible over-confidence) resulted in Moltke reducing the number of German attackers in France by 200,000 or more men in August. He transferred two corps to the eastern front to fight the Russians and assigned another two to besiege
Antwerp and
Maubeuge. The German 1st and 2nd armies on 1 August had 580,000 soldiers; at the Battle of the Marne they had 372,000. By the eve of the battle, the allied forces between Paris and Verdun numbered 980,000 French and 100,000 British soldiers while the Germans numbered 750,000. The Germans had an advantage in artillery with 3,300 to 3,000 guns.
The eve of battle By 2 September,
John Keegan said that "the German strategic effort, though neither Moltke nor Kluck perceived it, was beginning to fall apart". Moltke realized he did not have sufficient forces to carry out the Schlieffen Plan which envisioned Kluck's 1st Army encircling Paris to the west and south. Instead, he issued a Grand Directive changing the order of battle for the German attack. He ordered that Paris be bypassed on the north. The Germans would now attempt to entrap the French forces between Paris and Verdun. To accomplish this, Bülow's 2nd Army became the primary striking force, with the 1st Army ordered to follow in echelon to protect the western flank of the 2nd. At the time of this Grand Directive, Moltke based his decision on an intercepted radio transmission describing the French retreating across the Marne. Kluck, who was as bold as Bulow was cautious, was not pleased with the change of plans which would require him to halt his advance to wait for Bulow. Instead, interpreting the order broadly (or disobeying it), Kluck turned his line of march from south to southeast, becoming closer but not in echelon with Bülow, and on 3 September his forces crossed the Marne River east of Paris, the first Germans to do so. Kluck was in pursuit of the French 5th army which was still retreating. Kluck's boldness was based on his confidence that the French and British were a depleted and defeated force. He was unaware that a new French army, the 6th of Joseph Gallieni and Maunoury, was guarding Paris to his west and he discounted the British Expeditionary Force which had apparently abandoned the battlefield. The French commander Joffre was preparing for the propitious time to counterattack. He reinforced his newly created 6th and 9th Armies. On 3 September Joffre dismissed Lanrezac, commander of the 5th Army, and replaced him with
Louis Franchet d'Espèrey. This was done despite the fact Lanrezac had been right, as Joffre had been wrong, about the German offensive coming from Belgium and had also been right in violating the French "cult of the offensive" by taking a defensive posture against the invading Germans and preserving his army to fight another day. The French government fled Paris on 2 September fearing the Germans would conquer the city. On 4 September, while meeting with the British General
Henry Wilson, d'Esperey, the new commander of the French 5th Army, outlined a plan for a French and British counter-attack on the German 1st Army. The counterattack would come from the south by the 5th Army, the west by the BEF, and at the
Ourcq River by Gallieni and Manoury's new Sixth Army. Gallieni had come to the same conclusion on 3 September and sent Maunoury and the 6th Army east to find the German's flank. Joffre spent much of the afternoon of 4 September in silent contemplation under an ash tree. At dinner, he received word of d'Esperey's plan for the counterattack. That night he issued commands to halt the French retreat in his Instruction General No. 5 and ordered the counterattack to begin on 6 September. The BEF was under no obligation to follow orders of the French, but Joffre believed British participation to be crucial. Joffre first attempted to use diplomatic channels to convince the British government to apply pressure on BEF commander John French. Then, on 5 September, Joffre journeyed to BEF headquarters for discussions, which ended with him banging his hand dramatically on a table while shouting "Monsieur le Maréchal, the honour of England is at stake!" Following this meeting, French agreed to the operational plan to commence the following day. ==The battle==