The Allied Forces held the German army at the River Marne, forcing Germany to retreat. The British and French forces were slow to attack the retreating German First and Second Armies, mainly due to exhaustion and caution. The Germans halted their retreat at the Aisne on the 11th September. The German First and Second Armies, (commanded by von Kluck and von Bulow), were joined by the new Seventh Army. (Commander, von Heedingen). On the same day, entrenching began on the Chemin des Dames Ridge, which provided the German with a long and high position from which to conduct their defence. Whenever possible the German army would select the high ground for defence.
The French Fifth and Sixth Armies (commanded by d’Esperey and Maunoury), aided by the British Expeditionary Force (B.E.F. commanded by Sir John French) launched a frontal infantry assault upon the German’s defensive positions across the river at the Aisne upon their arrival on the 13th September. Most of the B.E.F. crossed the Aisne, on pontoons or partially demolished bridges, during the night of the 13th September.
The French Fifth Army crossed the Aisne and captured the Eastern tip of the Chemin des Dames. Louis XV had the ridge named after the Royal coach road built for his daughters. East of the Chemin des Dames, French armies had very little progress beyond the positions reached on the 13th September.
The B.E.F. advanced under the cover of the foggy night. As the mist evaporated under the bright morning sun, machine gun fire from the flank decimated their numbers. They were forced to begin digging in after Sir John French ordered the entire B.E.F. to entrench. Although neither side were not trained for trench warfare, the German Army adopted the system better. The Germans had ample supplies of siege howitzers and trench mortars, plus sufficient shells, which inflicted great losses to the Allied troops. By contrast, Britain had a shortage of heavy artillery and shells, and what they did have was not equal to the German artillery.
Establishing a bridgehead north of the river on the14th September, the Allies continued to assault the dug-in German forces on the higher plateau above. Within hours, the Germans had counter-attacked, forcing the Allies back. Germany used her heavy artillery and machine guns to defend her positions, demonstrating the superiority of defensive warfare against the offensive counterpart. Consolidation of the small advances could not be maintained, and by the 18th September, the Allies had scaled back the offensive. It finally became clear, especially by the Allies, the well-entrenched positions of the Germans could not successfully be attacked by direct frontal assault. The French were also finding themselves under increased pressure at Reims.
Both armies abandoned frontal assaults, on the 28th September, and began to try to turn the other’s flank. As the Germans aimed for the Allied left flank, the Allies similtaneously aimed for the German right flank. The period became known as the “race for the sea”. The Western Front was now established and stalemate descended
whereby both armies faced each other in trenches with a strip of land between which became “no mans land”.
The Western Front became a continuous trench line of approximately 400 miles, stretching from the Belgian channel town of Newport, south into France and eventually turning south east, right up to the Swiss border. By attacking and counter-attacking, the lines of trenches would vary throughout the war. The only Belgian city to stay in Allied hands was Ypres. For political reasons Ypres was required to be held in control by the Belgian/Allied Governments