Battle of The Frontiers - Prelude

Prelude

The objective of the French Plan XVII was to recapture the provinces of Alsace-Lorraine, lost in the Franco-Prussian War of 1870, pinning the German forces on the Rhine, and to attack the German centre through the southern Ardennes. In opposition to Plan XVII, the German Schlieffen Plan anticipated the target of the French assault and determined to remain there on the defensive, holding the Alsace-Lorraine front with the minimal possible force needed to keep the bulk of the French engaged there. The main German force would be on the right wing, sweeping through neutral Belgium and then into France, descending on Paris and executing a massive envelopment manoeuvre which would trap the French army between the two German forces and lead to its rapid annihilation. The German divisions would then rapidly turn about to face France's ally, Russia, on the Eastern Front. The German plan falsely assumed Britain, not formally allied with either side, would remain neutral in the conflict, and deemed the relatively small British regular army too small to be of any impact even if it did get involved.

France's frontier defences were based on a fortified zone from Verdun to Toul and isolated fortresses such as Épinal and Belfort. To the north, France relied on the impassable terrain of the central Ardennes forest and the promise of Belgian neutrality. Thus Plan XVII called for a two-pronged offensive, north and south of the Verdun-Toul line. In the south, the First and Second Armies would attack into Lorraine. In the north the Third, Fourth and Fifth Armies would attack through the southern Ardennes towards Luxembourg. On the left flank of the Fifth Army, facing the Belgian frontier, was the BEF which concentrated near the fortress town of Maubeuge.

On the French frontier, the German forces roughly matched the French in numbers and disposition, even to the point of being divided north and south of a fortified zone between Metz and Thionville. However, in Belgium to the north, opposing the French Fifth Army and BEF, were the German First, Second and Third Armies, forming the mass of Schlieffen's right wing.

Germany invaded Belgium on 4 August 1914 and began to besiege Liège. Despite evidence of German forces massing east of Liège, General Joseph Joffre, the French Commander-in-Chief, dismissed the threat to his northern flank and persisted with Plan XVII. Indeed, Joffre welcomed the prospect of a strong German right, which would mean the German left wing against which his offensives were directed would be weaker — in 1913, General Nöel de Castelnau, then Deputy Chief of the French General Staff, declared a German attack through Flanders was "so much the better for us" and that opinion still prevailed amongst the French high command. Even as the German armies began flowing through Belgium in mid-August, Joffre's Assistant Chief of Staff, General Henri Berthelot said:

"If the Germans commit the imprudence of an enveloping manoeuvre through northern Belgium, so much the better! The more men they have on their right wing the easier it will be for us to break through their centre."