At the beginning of the First World War, popular opinion was that it would not last more than four months. It was also believed that the science of modern warfare would be so deadly that mankind would demand cessation of such barbarism. The failure to anticipate the severity of war, and to be unprepared for the unexpected, lead both sides of the war to experience high casualties and deaths from the years of trench warfare. Germany's lack of planning resulted in the failure to completely execute the Schlieffen Plan. And because Britain was unprepared, they were unable to win the Battle of Somme. .
The Schlieffen Plan originated from Kaiser Wilhelm's desire to be able to fight a war on two fronts against France and Russia simultaneously. The idea of the plan was to cause the fall of France in approximately 39 days. The plan called for the German army to skirt the cities and to surround Paris and ultimately capture the French army, which in turn would cause them to surrender. That was one front. Germany figured that it would be able to force the surrender of France before the Russian army was able to gear up. The Russian army was known to be slow moving. The Schiefflen Plan was initially put into place in 1905. It was modified in 1911 in two ways; the Germans were not going to enter France from the Netherlands, only Belgium and the new German chief of staff made the decision to pull German troops off the northern front and put them on the Russian Front. .
The unexpected happened and caused the German's plan to fail. The Belgian people fought back against the German's slowing their progress in Northern France; the French were able to mobilize their troops much faster than expected and most importantly, the Russian army mobilized very fast. All of these things lead to the failure of the Schlieffen Plan. The failures in the West resulted in defeat at the First Battle of Marne in September, 1914, a stalemate, trench warfare and a two front war for Germany.