After the attack of the German right wing by Maunoury's army, the English army and Franchet d'Esperey's army threatened to break the communication between the first and second German armies and cause their hasty retreat which was reflected gradually all along the front.
VERDUN
DURING THE BATTLE OF THE MARNE
After the French manœuvre at the frontiers was checked and with the threat of a German envelopment in the West, General Joffre steadfastly withdrew from the battle and ordered a general retreat until the moment when the French troops were reunited. As soon as a favourable moment offered, it would be possible to take up a position and then to drive back the enemy.
The plan was as follows: to carry out on the left a mass movement (6th Army under Maunoury) to outflank, at the propitious moment, the German right, while a general attack or at any rate a desperate resistance should take place on all the rest of the front, from Paris to the Vosges.
The enemy's objective was first of all to wipe out the allied forces, the right having instructions to pursue the French left and the English army, before turning upon Paris which was to be seized like a plum ready to be picked! In the centre, the Crown Prince was in command of the pursuit: he saw his fourth cavalry corps pushing out their scouts towards the line, Dijon-Besançon-Belfort.
Here were dreams of triumph destined to give place to surprise, then doubt and finally the bitterness of defeat.
On September 5th, Gallieni reported the Germans creeping towards the South-East. The moment for the French manœuvre had arrived and Joffre launched the general offensive.
On September 6th-7th, the Sixth Army attacked the German right wing. To guard himself against this flank menace, Von Kluck brought up three army corps in succession from his frontal attack.
September 7th-8th. This diminution of strength allowed the English Army and the second French Army under Franchet d'Esperey to advance.
September 9th-10th. The Second Army threatened to cut off the contact between the First and Second German Armies and to take them in rear. Under this threat they determined upon a hasty retreat the effect of which made itself gradually felt along the whole of the German front (September 10th-13th).