On July 12, Foch ordered a counter-attack to be made on the western flank of the Château-Thierry salient. Leaving to General Gouraud in Champagne, and to General Berthelot between the Marne and Rheims, the heavy task of holding up the enemy “peace offensive,” Pétain organised the concentration of the armies of Generals Mangin and Degoutte, which were placed under the orders of General Fayolle. Thus, at the time the Germans were concentrating towards the eastern flank of the salient, the Allies were executing a similar manœuvre in the direction of the western flank. These two moves explain the whole battle, for while every enemy move was being closely observed and the bare minimum of troops used to hold up their attack, the Allies’ powerful concentration in the Villers-Cotterets Woods entirely escaped the enemy’s notice. This admirably camouflaged concentration was completed in three nights. To make the surprise still more effective, it was decided to attack without artillery preparation, it being left to the tanks to make good the deficiency. [Illustration: GENERAL MANGIN.] The objective was the Fére-en-Tardenois Railway, the only line of communication of the hundreds of thousands of Germans massed in the Château-Thierry “pocket.” Should this railway be captured or cut by gun-fire, the German armies would no longer be able to maintain themselves south of the Vesle. From the Aisne to the Marne, the German front was held by part of the 7th Army (Von Boehn), _i.e._ twelve divisions in echelons and eight divisions in reserve. Opposing these forces, from north to south, were:-- The 10th Army (General Mangin), from the Aisne to the Ourcq, comprising the 1st, 20th, 30th, and 11th French Corps, 1st and 2nd American Divisions, and the 15th Scottish Division. [Illustration: THE OPPOSING FORCES DURING THE ALLIES’ COUNTER-OFFENSIVE OF JULY 18.] The 6th Army (General Degoutte), from the Ourcq to Château-Thierry, comprising the 2nd and 7th French Corps, and the 14th and 26th American Divisions. This gave, in all, the equivalent of about twenty-one divisions (one American division being numerically equal to about two French divisions). At dawn, on July 18, without preliminary bombardment, and preceded by hundreds of tanks and a formidable creeping barrage, the attack was loosed along a twenty-seven-mile front. The surprise was complete and the effect crushing. The enemy front was pierced, strongholds reduced and organised woods and farms captured, their garrisons surrendering in hundreds, while the agricultural detachments were taken at work in the fields. [Illustration: THE ALLIES’ ADVANCE ON JULY 18 AND 19 (18/7 AND 19/7).]