Battle of Lorraine, 1914: Plan XVII marches into a trap

For the French, Lorraine was more than a border. Alsace and the northeastern part of Lorraine, roughly today's Moselle department, had been German since the Franco-Prussian War of 1871, and recovering them was the great aim of French policy. Plan XVII, France's war plan, massed most of the army in the center and south and called for an immediate offensive across the border.²

General Joseph Joffre, the French commander, also misread the enemy. David T. Zabecki writes in HistoryNet that Joffre did not believe Germany would put its reservists into the front line at once, and so concluded that it lacked the men for a great sweep through Belgium. That sweep was exactly what the German plan intended. In the south, Zabecki writes, the German Sixth and Seventh Armies were to tie down as many French troops as possible and keep them away from the decisive battle in the north.³

Four days of easy advance

A first French attack into southern Alsace, launched on 7 August, had taken Mulhouse and lost it again within days. On 14 August the main offensive began. General Auguste Dubail's First Army crossed into southern Lorraine toward Sarrebourg, and General Édouard de Castelnau's Second Army, to the north, advanced on Morhange. They believed they faced six German corps at most; HistoryNet says they faced nine. Opposing them were the German Sixth Army under Crown Prince Rupprecht of Bavaria and the Seventh under General Josias von Heeringen.⁴

The Germans kept in contact and pounded the columns with artillery as they toiled over poor roads, but gave way. By 17 August, HistoryNet writes, the French were as far as 25 miles inside German territory, and Dubail's First Army had taken Sarrebourg.⁵

The counterstroke at Sarrebourg and Morhange

The advance had cost the French more than distance. The Germans fielded proportionally many more heavy guns and howitzers, as well as more machine guns, than the French, whose field artillery relied almost entirely on the light 75 mm gun. A gap had also opened between the two French armies. Dubail ordered a night attack on 19 to 20 August to close the gap.⁶

Rupprecht, meanwhile, had refused German headquarters' suggestions that he fall back further and said he would attack unless ordered not to; headquarters neither approved the attack nor forbade it. On 20 August the two sides collided head on. By the afternoon the First Army had been forced out of Sarrebourg, and the Sixth Army turned on the Second Army near Morhange and overwhelmed it. By 22 August de Castelnau's men were back across the Meurthe, their starting line. The First Army had to fall back to the same line. The picture at the top of this page, a French magazine illustration of 1915, shows a heroic charge at Morhange; it was in fact a heavy French defeat.⁷

The Grand Couronné and the Charmes Gap

The German plan expected the battle to end there, with the French pinned on the Meurthe. Instead the Germans pressed on: HistoryNet writes that on 22 August the chief of staff, Helmuth von Moltke the Younger, for once issued a specific order, directing the Sixth Army to pursue toward Épinal. The French dug in on the fortified heights of the Grand Couronné in front of Nancy; according to HistoryNet, de Castelnau seriously considered giving them up, but Foch, commanding his XX Corps, protested and Joffre insisted that Nancy be held. In a French counterattack on 24 August, Foch's XX Corps struck the rear of the German advance, and orders from German headquarters to push through the Charmes Gap and cross the Moselle proved impossible to carry out.⁸

The Germans attacked the Grand Couronné on 4 September with a heavy bombardment. By 7 September de Castelnau was again recommending the abandonment of Nancy, and again Joffre refused, as the Battle of the Marne was now raging to the west. On 8 September German headquarters rationed the Sixth Army's artillery ammunition, and the offensive ground to a halt. On 12 September the Germans began to withdraw, and the French followed as far as the Seille, where the front in this sector stayed for the rest of the war.⁹

What Lorraine meant

HistoryNet puts the losses on both sides in the fighting south of Metz, from 7 August to 13 September, at some 350,000 to 400,000 men, in a battle that is now almost forgotten. Zabecki writes that the French, on interior lines, could shift divisions from the Second Army north to the Third, and Foch, whose XX Corps had fought in Lorraine, was given the new Ninth Army, which the British official history records was formed on 4 September between the Fourth and Fifth Armies.¹⁰

In Germany, Rupprecht was blamed for a while for pressing his own offensive instead of sending troops north. HistoryNet judges that the real responsibility lay with Moltke and his headquarters, which suggested, recommended and changed their minds instead of giving orders. The French learned the harder lesson. Plan XVII's faith in the offensive had cost them dearly in the first weeks of the war, and the line of trenches that formed in Lorraine was among the first signs of what the war would become.¹¹