South of the Ourcq the Allies were even more successful in gaining ground. Here the French and Americans, cooperating, drove the Germans back nearly a mile beyond the Château-Thierry-Soissons road. Meanwhile, in the Montdidier sector, Foch struck a hard blow at the enemy and achieved a brilliant success. The French troops, attacking on a four-mile front north of Montdidier, made a forward drive of two miles, capturing Mailly-Raineval, Savillers, and Aulvillers. The heights commanding the Avre River were also won, and over 1,500 Germans were captured. At other points, notably east and northeast of Château-Thierry, at the bottom of the great salient, the French troops, ably assisted by American forces, gained ground. Along almost the entire line between the Ourcq and the Marne German resistance was broken by the resistless onward sweep of the Franco-American forces. During the night of July 23-24, 1918, the Germans delivered a terrific counterattack in the neighborhood of Epieds, where they were opposed by American troops. The Germans succeeded after a hard fight in recapturing the village, and another in the neighborhood, but they were unable to hold their gains. On the following day the Americans drove them out of these villages and pushed on beyond Courpoil, more than a mile to the northeast. North of this fighting area French troops had penetrated as far as Brecy, while to the southeast French and American troops drove forward through the woods on a wide front beyond Preloup on the Marne. The advance of the Allies at several points was about two miles. The Germans had nearly half a million troops concentrated in the Marne salient. Attacked on three sides by British, French, and American forces, their position was extremely perilous. To continue resistance in a position so threatened might appear to be an act of madness, yet it was a maxim of Napoleon's that, where forces are about equal, the inside fighters have the advantage over an adversary in concentric formation. The Allies continued to bend in the salient, the French and Americans on the west, and the French and British on the east. The most important point held by the Germans, and the Allies' main objective, was Fère-en-Tardenois, the junction of several roads, and a chief distributing point. This nerve center of the German front, subjected to constant cross fire from French and American guns, was fast becoming untenable. Indeed there was no corner of the salient where the Germans were not constantly harried by the artillery of the Allies.