The First Battle of the Marne, also known as the Miracle of Marne, was a battle on the western front of the First World War. The battle took place from September 5 to 9, 1914. In this battle, the British and French allied forces jointly defeated the German Imperial Army.

in this battle, the warring sides invested about 1.5 million troops, with nearly 5, casualties (the French army lost more than 25, people, the British army lost more than 13, people, and the German army lost more than 22, people). Both sides made mistakes in this campaign: Xiao Maoqi didn't know the situation of the front line, commanded improperly, and the troops lacked coordination, which led to the bankruptcy of the quick victory plan; The British and French Coalition forces were slow to move and lost their fighters, which saved the strength of the Germans. The strategic significance of the Battle of Defamarne lies in that it made France avoid a total military collapse, reorganized a new defense line, and made the western front battlefield of World War I form a stalemate. In this way, Germany lost the opportunity to defeat France quickly and then turned around to deal with Russia, and fell into the bad predicament of fighting on the east and west fronts, laying the groundwork for Germany's defeat.

Colonel Bauer, a German staff officer, once wrote down this scene: "The desperate chief of staff (Xiao Mochi) said to the emperor (William II) with a pale face, Your Majesty, we lost the war."