The Marne September 5-9, 1914 Strategic Context As more states join the growing European conflict, Germany seeks to avoid a simultaneous, two-front war against both Russia and France by initiating the Schlieffen Plan; this involves outflanking French forces through Belgium with the bulk of the German Army to knock France out of the war. Britain surprises Germany by entering the war on the Franco-Russian side and sending an expeditionary force to the continent while France initiates Plan XVII; this involves bluntly attacking German forces in Lorraine. The initial Battles of the Frontiers are disastrous for French forces which must retreat but also encourage German commander, Helmuth von Moltke, to modify the Schlieffen Plan by shifting forces away from the right wing to the left wing and Eastern Front. French commander, Joseph Joffre, continues to withdraw until politicians force him to halt just south of the Marne River to defend Paris. By Jonathan Webb, 2010 © Stakes + A German victory would capture Paris, conceivably knocking France out of the war. + A French victory would prevent Germany from winning a quick victory and ensure a long, drawn-out conflict which Germany is not suited to fight.

 German Army  Well  Alexander von Kluck The Marne, 1914 Strength  French Army & allies  Well  Joseph Joffre  23 infantry divisions  41 infantry divisions  Helmuth von Moltke By Jonathan Webb, 2010 ©  8 cavalry divisions  700,000 men  5 cavalry divisions  535,000 men  Sir John French

German Army (Moltke) Moltke’s forces are organized in three armies although he exercises little control over them, particularly Kluck’s massive 1. Army. Kluck underestimates the strength of the two armies opposing him in the west and believes French 5. Army to be the vital left flank unit of French forces; he decides to reject the Schlieffen Plan’s maneuver to capture Paris by advancing southwest and enveloping the city and instead plans to advance south and rolling up the entire French Army. Joffre’s forces are organized in five armies although the British Expeditionary Force is far from the frontline and its reliability is ambiguous. Joffre plans to envelop the German right flank with 6. Army while the rest of his forces hold against any German attacks and be prepared to attack when the opportunity arises. 4. Army (de Cary) 9. Army (Foch) 5. Army (d’Esperey) BEF (French) 6. Army (Manoury) 3. Army (Hausen) 2. Army (Bülow) 1. Army (Kluck) As French 6. Army prepares to launch its offensive, Gronau – German commander along the Ourcq River – becomes suspicious of French intentions; he abruptly attacks French advanced units and drives them back. Gronau soon finds his forces outnumbered by French 6. Army and retreats before Manoury’s counterattack can strike him. The Marne River front stabilizes as each side prepares for aggressive operations. As combat on the Ourcq front escalates, Kluck changes his objective once again and resolves to destroy the weaker French 6. Army and capture Paris; German 1. Army begins to disengage from French 5. Army – which is attacking – and redeploy on the Ourcq to save the German right flank and rear. Joffre adds the left wing of Foch’s 9. Army to the offensive but little progress is made and Foch’s right wing is surprised by a combined attack by German 2. and 3. Armies; hasty counterattacks prove ineffective. Joffre orders de Cary’s 4. Army to engage German 3. Army to prevent it from exploiting the success against French 9. Army. More German forces arrive on the Ourcq front, allowing Kluck to throw back Manoury’s offensive; even with French reinforcements to this sector, French 6. Army is strained and more German forces are still en route. Joffre takes advantage of these transfers with an aggressive attack on the Marne front by d’Esperey’s 5. Army. Meanwhile, Foch’s 9. Army struggles against a determined offensive, including a sharp night attack by Hausen’s 3. Army until attacks by French 5. and 4. Armies against German 2. and 3. Armies relieve some pressure. As fierce fighting continues along the front, a gap between the German 1. and 2. Armies becomes more pronounced which Joffre hopes to exploit by coasting French’s BEF to the frontlines. Making matters worse for Moltke’s armies, a total lack of communication between his 1. and 2. Armies prevails. Kluck launches the largest attack yet against French 6. Army and drives it back towards Paris, but widening the gap between German 1. and 2. Armies as a result. Meanwhile, French 5. Army is able to completely outflank German 2. Army and force it to retreat east, further widening the gap. Joffre orders his French armies to pin German forces and the BEF to advance through this growing gap to encircle German forces but it is moving slowly. Moltke, disturbed by the lack of fresh reports from the front, sends relatively junior staff officer Hentsch to clarify the situation and order a withdrawal if necessary. 1. Army (Kluck) 2. Army (Bülow) The BEF continues its sluggish advance against scarce German resistance while the rest of the front engages in fierce combat. German 1. Army holds the initiative against French 6. Army but French 5. Army holds the initiative against German 2. Army. The battle is ended by Hentsch’s order to withdraw after learning of British forces pouring into the gap. He finds German 3. Army’s position to be most favourable but 1. and 2. Armies completely at the mercy of the enemy forces occupying the vast gap between them. Kluck, although he feels he could sweep French 6. Army from the field, respects the General Staff enough to promptly withdraw. German 1. Army retreats north and 2. and 3. Armies northeast with only intermittent fighting until they reach better defensive positions. Paris Ourcq River Landmarks St. Gond Marshes Marne River French Army & allies (Joffre) German Army (Helmuth von Moltke) 535,000 men 23 infantry divisions 5 cavalry divisions French Army & allies (Joseph Joffre) 700,000 men 41 infantry divisions 8 cavalry divisions

The Marne, 1914 Casualties & Aftermath French Army & allies:German Army: ≈64,000 or 9% ≈40,000 or 7.5% By Jonathan Webb, 2010 © French forces were unable to seriously hinder German forces in their retreat. Both sides attempted to outflank each other’s northern flank until they ran out of land to maneuver on. Erich von Falkenhayn replaced Moltke as German commander and launched repeated attacks against the French fortress of Verdun and growing British forces in Flanders, all unsuccessful. German forces were able to win the vital St. Mihiel salient which was not seriously threatened until 1918 when combined Franco-British-American forces defeated the German Army.

The Art of Battle: Animated Battle Maps By Jonathan Webb, 2010 ©