In 1914, Germany believed war with Russia was extremely likely. If war broke out, Germany assumed France would also attack as she was both an ally of Russia and keen for revenge for her defeat in the Franco-Prussian war. If this happened, Germany would face a war on two fronts. Germany wanted to avoid this at all costs. Germany planned to defeat France rapidly and then turn to the eastern front for a major offensive on Russia. This was the basis for the Schlieffen Plan.

The Germany Army Chief of Staff, Alfred von Schlieffen was asked to plan a way of preventing a war on two fronts. His initial plan was produced late in He believed that it was a priority to defeat France quickly, forcing them to surrender before Russia had a chance to mobilize her armed forces.

In full knowledge of French defences, Schlieffen proposed attacking France through Holland, Belgium and Luxembourg – the Benelux countries. Schlieffen planned to use 90% of German military forces to deliver a knock out blow to France. The remaining 10% would defend the eastern border of Germany against Russian attack

Von Molkte replaced Von Schlieffen in 1906, and made some alterations to the plan. His version avoided invading Holland, instead concentrating attack through Belgium. According to Von Molke, the Belgium army would be unable to resist a powerful German military, and German forces would rapidly enter France

Assumptions Russia would take at least 6 weeks to mobilize. France would be easily defeated in 6 weeks. Belgium would not resist any German attack. Britain would remain neutral.

The Reality On 2nd August 1914, the German army invaded Luxembourg and Belgium according to the Schlieffen Plan. The Germans were held up by the Belgium army, backed up by the BEF (British Expeditionary Force) which arrived extremely quickly. Russia mobilised in just 10 days and Germany was forced to withdraw troops from the Schlieffen Plan to defend her eastern border. Germany did not take the chance to take Paris, instead decided to attack east of the capital. They were met by French at the battle of the Marne (5-11 Sept) which halted the German advance.

While Approaching Paris from the west, the German forces were forced to turn south too soon. This meant that the French army at the French-German border could now reach them. The Germans were also attacked by French troops moving out from Paris and British troops from the Channel ports.

The German advance was halted on the Marne River. Both sides "dug in" and built extensive trench systems. These trenches were protected by artillery, barbed wire, and machine guns. The Schlieffen Plan failed. Instead of knocking France out of the war, the Germans found themselves trapped on the Western Front and fighting Russia in the east. Instead of a short, swift campaign, Germans attack on France became a long, costly war.