First Battle of the Marne

The World War I First Battle of the Marne featured the first use of radio intercepts and automotive transport of troops in wartime. After French commander in chief Joseph Joffre ordered an offensive in September 1914, General Michel-Joseph Maunoury’s French Sixth Army opened a gap between Germany’s First and Second Armies. Maunoury exploited the gap with help from the French Fifth Army and British Expeditionary Force, while Ferdinand Foch’s Ninth Army thwarted the advances of the German Second and Third Armies. By Sept. 10, the Germans embarked on a retreat that ended north of the Aisne River, beginning a phase of the war that would be marked by trench warfare.