A stalemate developed on the Western Front as a result of the failure of the German Schlieffen Plan. There were many reasons that the Schlieffen plan failed.

The Russians took a lot less time to mobilize than the Germans expected. Germans had estimated that the Russians would take about six weeks to mobilize. In fact, Russia invaded Germany on August 17th. The Germans were forced to transport many of the troops from Belgium to the eastern front so that they could fight the Russians.

The French 'Plan 17' failed. The plan was to swiftly attack Germany, defeat them and win back Alsace-Lorraine. However, the French could not get through the German defences at Alsace-Lorraine and many French troops were lost. The French now had to rush to stop Germany from reaching Paris and trapping their armies.

On the 23rd August, the Germans were delayed by the BEF (the British Expeditionary Force) at Mons. The BEF then went south and joined the French. The Germans still went into France but they could not encircle Paris because they lacked soldiers (the army had been split in half because they had to fight the Russians). The Germans were counting on being able to encircle Paris and they wanted the French to sign for peace. The Germans wanted to hold onto their land and they hoped to gain more land from the French. The French army that was left from the failed Alsace-Lorraine attack reinforced the French army that was retreating from the Germans. The French General, Joffre, wanted the French to keep fighting, and he rushed remaining troops to the front.

Over the four days of the battle of the Marne (5th-9th September) the Germans became very tired. The French resistance was much better than expected. The Germans began to dig themselves into trenches. The German Commander, Moltke, lost complete control of his armies as he was too far from the front and the German casualty figures were so huge that they were not published.

The war became a race to the sea, each army wanted to capture the Channel ports and they both started to travel north. On 8th October the Germans captured Ostend and they captured Antwerp on the 15th. British marines tried to stop them, but they were defeated.

However, on the 18th October Ypres, Belgium, was recaptured from the Germans and the channel ports were reached by the British and French first. The Germans had lost the race to the sea. This meant that both sides had to resort to trench warfare. Both sides began to dig in, making defensive positions stretching from the North Sea to the Swiss border with France.

The German Schlieffen plan and French Plan 17 had both failed, so neither army had a clear idea of what to do. Neither army wanted to move from their defensive positions as it became very dangerous to do so, therefore a stale mate developed.