When Germany began its westward advance in August 1914, it hoped for a quick victory; however, it ended up being the first act in what would become a global conflict: World War I. Germany had been planning for war with France for more than a decade, but the conflict did not work out as commanders had planned. A month after the soldiers left Germany, their advance was halted at the Battle of the Marne.

The Schlieffen Plan

Germany’s initial attack on France was based on the so-called Schlieffen Plan, developed by German commanders between 1897 and 1906 and named after Count Alfred von Schlieffen, chief of the German Great General Staff. The plan involved a fast German advance westward into France and Belgium, with troops swinging south to capture Paris and quickly knock France out of the war. This action would spare Germany from having to conduct wars on both its western border, against France, and its eastern frontier, against Russia.

Initial Advance

On Aug. 4, 1914, the German army crossed the border into neutral Belgium. Belgium had refused the Germans permission to move through its territory, meaning the German soldiers had to fight every step of the way. The French plan to resist a German offensive involved making their own attack on the disputed border regions of Alsace-Lorraine, and on Aug. 7, the first French troops moved eastward into this area. Fierce battles took place in mid-August between the two armies at Lorraine, Ardennes, Charleroi and Mons. By the third week of August, the first British soldiers had arrived to reinforce the beleaguered French.

Battle of the Marne

The German advance slowed in late August and early September, and was finally blocked by the Battle of the Marne between Sept. 5 and 9, 1914. The Germans altered the direction of their advance toward Paris, making them vulnerable to a counter-attack. French and British forces repeatedly attacked the advancing Germans on a 100-mile-wide front east of Paris. British units created a gap between the two main bodies of German troops, forcing the German commanders to order a retreat. After the battle, German commander Helmuth von Moltke told the kaiser, "We have lost the war."

Battle Outcome

After the Battle of the Marne, the exhausted German troops withdrew to the valley of the Aisne River, where they created strong defensive positions. From these, they were able to resist French and British attacks, forcing the fighting northward as each side attempted to get behind the other’s front line positions. This so-called “Race to the Sea” eventually resulted in the creation of the trenchlines that formed the Western Front and proved the starting point for more than four years of largely static trench warfare.