On September 3 the British forces were in position south of the Marne between Lagny and Signy-Signets. Up to this time I had been requested by General Joffre to defend the passages of the river as long as possible, and to blow up the bridges in my front. After I had made the necessary dispositions, and the destruction of the bridges had been effected, I was asked by the French Commander in Chief to continue my retirement to a point some twelve miles in rear of the position I then occupied, with a view to taking up a second position behind the Seine. This retirement was duly carried out. In the meantime the enemy had thrown bridges and crossed the Marne in considerable force, and was threatening the Allies all along the line of the British forces and the Fifth and Ninth French Armies. Consequently several small outpost actions took place. On Saturday, September 5, I met the French Commander in Chief at his request, and he informed me of his intention to take the offensive forthwith, as he considered conditions very favorable to success. [Sidenote: General Joffre announces intention to take offensive.] General Joffre announced to me his intention of wheeling up the left flank of the Sixth Army, pivoting on the Marne and directing it to move on the Ourcq; cross and attack the flank of the First German Army, which was then moving in a southeasterly direction east of that river. He requested me to effect a change of front to my right--my left resting on the Marne and my right on the Fifth Army--to fill the gap between that army and the Sixth. I was then to advance against the enemy in my front and join in the general offensive movement. [Sidenote: Battle begins Sunday, September 6.] These combined movements practically commenced on Sunday, September 6, at sunrise; and on that day it may be said that a great battle opened on a front extending from Ermenonville, which was just in front of the left flank of the Sixth French Army, through Lizy on the Marne, Mauperthuis, which was about the British centre, Courtecon, which was on the left of the Fifth French Army, to Esternay and Charleville, the left of the Ninth Army under General Foch, and so along the front of the Ninth, Fourth and Third French Armies to a point north of the fortress of Verdun. [Sidenote: Battle concluded September 10. Germans driven to the line Soissons-Rheims.] This battle, in so far as the Sixth French Army, the British Army, the Fifth French Army, and the Ninth French Army were concerned, may be said to have concluded on the evening of September 10, by which time the Germans had been driven back to the line Soissons-Rheims, with a loss of thousands of prisoners, many guns, and enormous masses of transport.