Start of the Battle of Montdidier

On 8 August 1918, in the same thick fog in which the Canadians and Australians were breaking through the German front at Amiens, the French First Army of General Marie-Eugène Debeney went into the attack on their right flank. On a sector about 29 kilometres wide, from the Amiens–Roye road to the vicinity of Montdidier, it had ten divisions in the front line and four more in reserve, together with the II Cavalry Corps. That day the French took Moreuil, crossed the river Avre and advanced several kilometres onto the Santerre plateau. So began the Battle of Montdidier, the French part of the first great Allied attack of the offensive that was to end only with the armistice.

The plan

For the duration of the operation the First Army was placed under the command of Field Marshal Douglas Haig. This was the wish of Ferdinand Foch, Marshal of France for the previous two days, who at the end of July had decided that two armies attacking side by side needed a single commander. The French had no large concentrations of tanks, so unlike the British they could not attack by surprise without an artillery preparation. It was agreed that their artillery would open fire together with the British, and the infantry would move off 45 minutes later. Debeney wanted to bring his corps into action one after another, from west to east. The first to attack was to be the XXXI Corps of General Toulorge, the Canadians’ neighbour, in the direction of Hangest. Four hours later IX Corps was to cross the Avre and bite off a semicircular piece of the German position about 3 km deep, to cover the right flank of XXXI Corps. X and XXXV Corps at Montdidier were for the time being only to draw the Germans’ attention. The main blow, from Montdidier towards Roye, was planned for the following day.

The commander of the Reserve Army Group, General Émile Fayolle, who was still responsible for the composition of Debeney’s army, set it more ambitious tasks on 6 August: to force the Germans to abandon the line of the Avre, to recover Montdidier, taken by them on 27 March, and to prepare to outflank the hills between the Matz and the Oise. Debeney told his corps that the attacks were to proceed “by a series of bounds forward”, that they must not wait for their neighbours, and that the troops were “to go very far from the first day”. A few days earlier the Germans had themselves made the French task easier: on 3 August, not wishing to fight with a river at their backs, they had withdrawn behind the Avre and the little river Doms, blowing the bridges and leaving only outposts west of Montdidier.

Course of the day

The French artillery opened fire at 4.20 a.m., at the moment the British attack began. According to the historian of the 42nd Division, Colonel Grasset, its infantry had already pushed several hundred metres forward at zero hour without meeting resistance, but in accordance with the bombardment timetable it had to stop and wait. The whole of XXXI Corps moved off at 5.05 a.m. The Germans, who had been fighting the Canadians for three-quarters of an hour, were clearly surprised by the widening of the attack. The 42nd and 37th Divisions passed the woods north-east of Moreuil on both sides and between 9.30 and 10 a.m. reached the road from Moreuil to Villers-aux-Érables. The 66th Division took Morisel and then, going round it from the north and south, Moreuil. The time at which the small town was taken varies in the sources: from 7.30 to about 9.30 a.m. Erich Ludendorff later wrote that the units still resisting bravely at Moreuil had been “rolled up” by the breach the British had opened to the north.

On the Avre things went harder. After an artillery duel lasting almost four hours, IX Corps attacked at 8 a.m. During the night and the bombardment it had managed to throw footbridges across the river, but the crossing points were swept by German machine guns from the Genouville wood. One regiment of the 3rd Division crossed the river at Braches and seized a bridgehead at La Neuville-Sire-Bernard. Of the 15th Colonial Division only one battalion got across to the other bank, and it was soon held up by the road from Moreuil to Montdidier. Only the progress of XXXI Corps at Morisel allowed the colonial troops to force the river and, at about 11.30 a.m., take Genouville farm. West and south of Montdidier, X and XXXV Corps confined themselves to artillery fire.

In the afternoon the fighting moved onto the Santerre plateau. XXXI Corps brought the 153rd Division into action with two battalions of light Renault tanks and, according to the French official history, took Mézières-en-Santerre at 3 p.m. Grasset writes that the village was found already abandoned soon after noon, and that the Canadians had been level with it since the morning. At 3.30 p.m. Debeney ordered XXXI Corps to reach Arvillers that same evening “without fail”, and the 153rd Division to take Hangest-en-Santerre. German resistance, however, was stiffening. German reserves were arriving on the battlefield, among them the 1st Reserve Division, which had already sent counter-attack groups along the road from Amiens to Roye in the morning. The attack, renewed after fresh bombardments at 5.30 p.m. in front of Plessier and at 7.30 p.m. in front of Fresnoy, made slow progress. Plessier fell at about 7 p.m., and Fresnoy-en-Chaussée only at 9.30 p.m., more than five hours after the 4th Canadian Division had passed it. According to Grasset, the 42nd Division turned down the Canadians’ help through a misunderstanding, and one of the tank companies supporting the 153rd Division lost 13 machines out of 19. It was too late for Arvillers. During the night IX Corps pushed up to the western edges of Plessier and made contact with XXXI Corps.

Haig, Debeney and the cavalry

At 11.30 a.m., when the news from the Fourth Army’s front was already very good, Haig sent an officer to Debeney asking him to throw all his cavalry into the battle on the right of the British cavalry and strike at the rear of the Germans defending Montdidier. Debeney replied that his cavalry was far away and the roads were clogged with infantry, so it could not arrive before the morning of 9 August. In the evening, at 9.30 p.m., he issued orders for the next day which, according to the British official history, were intended to cover the British flank rather than to exploit success. XXXV Corps at Montdidier, which was to attack, was told to “be ready to attack on order”, and the cavalry remained in the area of Saint-Just-en-Chaussée, more than 30 kilometres from the junction of the armies at Le Quesnel.

The day’s balance

On 8 August the French advanced several kilometres, crossed the Avre and came out onto the Santerre plateau, and their left wing kept pace with the Canadians, albeit with a delay. According to the British official history they took 150 officers and 3,200 men prisoner from three German divisions. Some other accounts give about 5,000 prisoners. That was far fewer than the 12,000 prisoners of Rawlinson’s Fourth Army, but the French were attacking on a narrower sector, across a river and with less surprise. In his memoirs Foch summed up the day as a joint victory: the Allied front had moved forward more than 10 kilometres on a sector more than 20 kilometres wide, and more than 13,000 prisoners and 300 guns had been taken. The next morning his envoy went to Debeney with a reminder that the First Army was to reach Roye as quickly as possible, was not to send a single division to the rear, and was to “go fast, march hard”. Ludendorff called 8 August “the black day of the German Army”, and already on that day he decided that the right wing of the Eighteenth Army would have to be pulled back from Montdidier towards Roye.