The First Battle of the Marne, fought between the combined Allied forces and the Germans, was an important victory for the Allies in World War I because it stopped the German advance into France and in the rest of Europe. The first reason why it was crucial for the Allies to win this battle and thus stop the German advance was that it forced the Germans to give up their hopes of capturing Paris. At the beginning of World War I, Germany advanced through Belgium and into northern France. This German offensive plan was known as the Schlieffen Plan. This plan aimed to quickly defeat and conquer the French so that the Germans could focus solely on fighting the Russians. The British forces, known as the British Expeditionary Forces, as well as the French Fifth and Sixth Armies, were quickly pushed back from the Belgian border and forced to retreat. The Battle of the Frontiers, which preceded the First Battle of the Marne, was a German offensive that caused a major Allied retreat towards Paris. The Allies, not confident in their ability to keep the Germans away...