The Battle of the Marne by G.H. Perris — Read

It is now apparent that a record of the battle covering the whole front day by day would give no clear view of its development. The climax came not everywhere at the same hour, or even on the same day, but in a remarkable succession -- beginning on the Ourcq about noon on September 9, and immediately afterward on Foch's front (the two areas most directly menaced by the advance of French and d'Espérey), reaching de Langle de Cary the next morning, and Sarrail only on the night of the 10th. It remains to trace the completion of the victory.

Maunoury had failed of his objective: after four days of grinding combat, he had advanced his centre some 10 miles eastward, but was, at noon on September 9, still an average of 6 miles short of the Ourcq, before Vareddes, Etrepilly, and Acy-en-Multien; while his left was painfully bent back from the last-named point westward to Silly-le-Long. Every effort to obtain an effective superiority of strength, and to break through or around the enemy's right, had been thwarted by Kluck's speed in supporting that flank. Looking at this part of the field only, it might be supposed that a substantial reinforcement of either side at this moment would have precipitated a disaster on the other. A wider view shows a very different balance. If Maunoury could have found one or two fresh divisions, the German I Army might have been shattered; a further French withdrawal to and beyond the Marne would not have entailed any such grave consequences.