_The present positions must be held at all cost. The honour of each commanding officer is at stake_, proclaimed Gen. Pellé. Trenches were dug, and Mont Renaud organised. The road to Compiègne was barred and the hills to the south and south-west of Noyon became the pivot of the defences. Repeatedly attacked, Mont Renaud changed hands several times, finally resting with the French. The exhausted 10th Div. fell back on the _massif_ of Le Plémont, where the 77th Div. had just taken up its positions. However, although Gen. Humbert's right checked all enemy advance, Gen. Robillot's group and the first units of Gen. Debeney's Army, on the left, were unable to hold their ground in the Picardy Plain. Forming but a thin line, the enemy's powerful thrust opened gaps in places. Units of the 56th and 133rd Inf. Divns. and of the 4th and 5th Cav. Divns. under Gen. de Mitry, were pushed forward, with orders to establish the liaison, on their right, with the 22nd Div., and on their left, with the British who were falling back on the Santerre Plateau. This liaison was necessarily weak, as the troops had to be deployed. Fighting day and night for every inch of ground given up, these splendid troops succeeded in retarding the enemy's advance until the arrival of reinforcements on the line of the Avre. [Illustration: _The Germans attempted with their left to turn General Humbert's Army, strongly established at Le Plémont. Roye fell._] The exhausted 22nd Div. fell back, carrying with it the 62nd on its right. Roye, outflanked from the south and attacked on the north, was lost. A breach, opened between the 22nd and 62nd Div. was filled by an emergency detachment hastily got together on the spot by General Robillot. On the evening of the 26th, the front was established on the line Echelle-St.-Aurin, Dancourt, Plessis-Cacheleux. [Illustration: ROYE. THE PLACE D'ARMES AT THE END OF THE WAR.] General Humbert made a strong appeal to his men: _Let all commanding officers firmly resolve to accomplish their duty to the extreme limit of sacrifice, and imbue their men with the same spirit._ North of the Somme, the Germans took Albert--an important junction--but were checked further north, by the left wing of Byng's Army. [Illustration: THE MONT RENAUD.] Allied Unity of Command. Events had forcibly demonstrated the urgent necessity for Allied unity of command. On March 26, a War Council, composed of M.M. Poincaré, Clemenceau, Lord Milner, Haig, Pétain and Foch, empowered the latter to _coordinate the action of the Allied Armies on the Western Front_. "At the moment when Foch was to take precedence of Pétain and Haig, what was the position of the armies, as regards the directives of the High Command? In other words, how was the Anglo-French battle being directed? The position is defined in the General Orders of Pétain and Haig, the former of whom prescribed: "To keep the French forces grouped, to protect the Capital; _essential mission_;