On the night of August 18, 1918, the French launched an attack on a front of about fifteen miles east of Ribécourt and across the Oise to Fontenoy, six miles west of Soissons. The fighting, vigorously pushed on the following day, resulted in notable gains for the Allied arms. The capture of the village of Rimprez, on the west bank of the Oise on the Noyon-Compiègne road, was followed by an advance of two miles northward to the southern edge of Dressincourt. Equally important gains were made at other points in the line of attack. The plateau west of Nampcel and Morsain and several other villages were carried by storm. In the course of the fighting the French captured over 2,000 prisoners, including several battalion commanders. In the Lys salient the British continued the irresistible drive forward. Marshal Haig's advance was on a front of nearly six miles. His line was carried up to the town of Merville and to the north-and-south road through the town from Les Purebecques on the north to Paradis to the south. The victories of the French troops between the Oise and the Aisne gave them possession of the Oise Valley as far as Mont Renaud. General Mangin, who carried out these successful operations, was now in a position to force the enemy to resort to desperate measures to escape a serious defeat. His artillery now commanded all roads of importance, and the only exit available for the Germans from the region of Noyon and Lassigny was a narrow-gauge line running north to Ham by way of Guiscard and the highroad running in the same direction. Von Hutier had either to check Mangin's advance, or choose this narrow outlet for extricating his troops and material. Rather than face this alternative, the Germans were offering a desperate resistance in an endeavor to hold on to their present lines, hoping against hope that something might occur that would enable them to shake off the Allies' strangle hold. General Debeney's advance on Lassigny and Roye had slackened up owing to the stout opposition offered by the enemy, but he continued to make steady progress. In the early morning of August 20, 1918, General Mangin began an operation between the Aisne and the Oise southeast of Noyon and northwest of Soissons that achieved a splendid success. Striking on a fifteen-and-a-half-mile front he smashed into the German line to an average depth of two and a half miles, capturing seven towns and over 8,000 prisoners.