The History Hub.

The fronts were formed due to a plan that had been hatched by Germany before the war began.  This was called the Schleiffen Plan. Alfred von Schlieffen and the German high command had foreseen a war coming in Europe and the Schleiffen Plan was a battle plan designed to win the war for Germany without the country having to fight a war on two fronts. Fighting on two fronts was dangerous for Germany because it would mean it would have to divide it's forces. 

 

Essentially Schlieffen's plan was this; Germany was bordered on both sides by France and Russia respectively. France was the larger threat as at that time Russia was seen as backward and was not ready for war. Therefore Schlieffen calculated that an all out attack on France was best as they could beat the French and capture Paris before Russia was ready to fight. Once France was beaten, Germany could then take its troops back to its eatern border to fight the Russians. Britian was not factored into the plan as von Schlieffen felt they would not want to fight a war on the continent and would stay in Britain. This plan dictated Germany's movements in the early stages of the war. However, it did not go smoothly and the result was to set up the two lines of battle for the remainder of the war.

 

The early stages of war are known as the War of Movement. This is because, compared to the next four years of fighting during which both sides stayed in the same spot, both sides were actully moving forwards and backwards in open ground. Germanys intitial attack on France was hugely successful and it looked like the Germans would knock the French out of the war as they neared Paris. However, the French border was heavily defended. To avoid this difficult obstacle the Germans had simply gone through Belgium to reach France. Britain had guaranteed Belgium that if it was attacked in any way it would be assissted; the German movement through Belgium had bought Britain into the war. When the Germans were at the River Marne they were attacked by both the B.E.F (British Expeditionary Force) and the French together. The German advance was halted here and they were hit by another set back at the same time. The Russians were actually ready for war far quicker than von Schlieffen had thought and they attacked Germany with considerable success! The Germans then had to retrieve a number of their troops from France, further weakening their forces there, in order to fight the Russians. In the end the War of Movement ended and the Eastern and Western Fronts were formed where the two sides were fighting. Both sides dug in and Trench warfare began in earnest.