The Battle of the Frontiers of WWI (1914 to 18), fought between 14 and 25 August, involved a flurry of encounters between German and French, Belgian, and British armies as both sides attempted to cross borders and establish the fighting front in the enemy's territory. Germany hoped to advance through Belgium and fight the major battles of the Western Front in France, while the French wanted to attack the Franco-German frontier around Alsace and push the war into Germany. The German armies, thanks to their superior numbers and artillery, achieved their objective, albeit at a heavy cost in casualties, and, thereafter, the most intense fighting of the war took place on French soil.
The German Army had studied how they could best defeat France in the first few weeks of WWI, when, as anticipated, France, Britain, and Russia faced Germany and Austria-Hungary. The Schlieffen Plan was prepared way back in 1905 and had the objective of quickly knocking out France so that Germany could then turn to Russia in the east and so not have to fight on two large fronts at the same time. The plan required German forces to quickly move through the neutral Low Countries, avoiding the main French fortifications on the Franco-German border. The plan was to attack the French lines from the rear, capture Paris, and gain a surrender in six weeks, the time the German generals thought it would take Russia to fully mobilise its armies.
The Schlieffen Plan was highly ambitious, and even the German generals acknowledged they probably did not have enough troops to accomplish it. The plan was additionally weakened by the decision to only go through Belgium (between Antwerp and Liège), narrowing the route into France and potentially causing logistical blockages. This is, in fact, what happened.
Britain had hoped to remain neutral in a continental war but was obliged to uphold Belgian neutrality via a treaty the two states had previously signed. In any case, Britain could not stand by and see France crushed and a new Europe formed that was totally dominated by Germany, its greatest economic and military rival in Europe. Britain informed the German government that a mobilisation through Belgium would result in Britain declaring war on Germany. On 3 August, German troops marched through Belgium anyway, and Germany formally declared war on France (and vice versa). On 4 August, Britain declared war on Germany.
Mobilising at the end of July, the German forces led by General Alexander von Kluck (1846 to 1934) encountered their first holdup: unexpected Belgian resistance at Liège's ring of 12 forts. By 14 August, the German forces had brought up their giant artillery pieces, the 'Big Bertha' howitzers with 30.5 and 42 cm (12 and 16.5 in) barrels that pounded the fortresses into submission. The Germans now moved on through Belgium, captured Brussels on 20 August, and marched on to directly face the French army. In order to protect their rear, German troops were encouraged to implement the policy of Schrecklichkeit ('frightfulness'), which was to terrorise and subdue the local people by destroying property and carrying out executions. Amongst the horrors, Belgian culture also suffered; the medieval manuscripts of the Louvain library went up in flames, a priceless repository of human history lost forever. Crucially for the advance, some German troops had to be siphoned off to face Belgian troops around Antwerp, Namur, and Maubeuge. The timing of the German plan was still more or less intact, but the number of German men lost or diverted in Belgium would be regretted a week or so later.
As the fighting reached French soil, there were still no fewer than seven German armies facing five French armies and one British, the British Expeditionary Force (BEF). The British force was composed of around 70,000 men, a small one in the grander scheme of things, but all of these men were professional soldiers, unlike the conscripted men in other armies. What developed next, as all these soldiers clashed, was a complex series of fronts consisting of four main battle areas, which stretched from Mons in Belgium in the north to the Franco-Swiss border in the south.
The French army was marching northwards since this had been their generals' premeditated plan for how best to quickly win the war, an idea known as plan XVII. The French objective was to take the region of Alsace-Lorraine, which Germany had controlled since they had won the Franco-Prussian War of 1870 to 71. In case German forces entered Belgium, Plan XVII stipulated that two French armies were to be directed there. Which is exactly what happened. Thus, there was a 'battle for the frontiers': Germany in the north, going through Belgium, trying to create a giant encirclement when they ultimately recrossed the Franco-German border, and France further south around Alsace, each side hoping to defeat the enemy with one heavy blow. Unfortunately for both sides, the French badly underestimated just how many troops Germany would send through Belgium, and the Germans underestimated just how difficult their plan would be to put into reality when facing stiff resistance from a determined enemy.
At the Battle of Loraine, two French armies entered German territory on 14 August. The First Army, led by General Auguste Dubail (1851 to 1934), was obliged to retreat after meeting a numerically superior German force composed of two armies, the Sixth, led by Crown Prince Rupprecht (1869 to 1955), a courageous but perhaps overly pessimistic commander, and the Seventh, led by the experienced Josias von Heeringen (1850 to 1926). Dubail moved back to the far side of the Meurthe River, and his troops dug themselves in. The Second French Army, led by General Noël Édouard Castelnau (1851 to 1944), lost the Battle of Morhange to Rupprecht's Sixth Army on 20 August. The French lost 20,000 men and 150 artillery pieces in this battle. The Germans then advanced through the Vosges, but Castelnau managed to defend a new front at Le Grand Couronné, which followed the Moselle River, and so, at least the city of Nancy was kept in French hands. Plan XVII had failed.
Meanwhile, on 21 August, the French Third and Fourth Armies advanced northwards, hoping to attack the flank of the German advance through the forested Ardennes. When the two sides met, there followed four days of heavy fighting in foggy conditions. Eventually, the numerically superior German Fourth and Fifth Armies pushed through, and the French were obliged to retreat and hold a line around the fortress complex of Verdun. It was perhaps only at this moment that the French high command fully came to realise just how wide the German advance was and that the enemy was attacking with a formidable strength in depth thanks to their use of reserves.
A private in the French Army, François Dolbau, describes what it was like to face the attack, particularly the enemy's formidable artillery:
Well you see when we arrived near Morhange everybody was expecting to go along without much damage, you see, but when we arrived on the trenches of the Germans we could hardly see them because they had special uniforms. And then we could do nothing – absolutely nothing – except to wait. And then at night-time the Germans were shooting us and shelling us too, very heavy shelling you know, we lost a lot of people there, it was awful. Our battery was a very good battery. We had a very good gun, the 75 gun, but not being sufficient in quantity to do any harm to the Germans because they were covered in trenches you know.
(Imperial War Museums)
Further to the west, the German Fourth Army was making good progress, too. Commanded by General Karl von Bülow (1846 to 1921), the Germans went through the Liège corridor, won the Battle of the River Sambre (22 to 3 August), and then laid siege to the Namur fortress, which was captured on 25 August. To the left of Bülow, the German Third Army took Dinant on 15 August. Once again, the German superiority in artillery and the French commander's lack of comprehension of the damage well-entrenched machine-guns could do to charging infantry were telling factors in victory. The French had also been surprised that the main German advance was not further east, as they had expected.
Once again, thanks to superior numbers and artillery, the German First Army, led by Kluck, gained victory, this time against the British at Mons in Belgium (23 August) and at Le Cateau (26 August) on the far left of the Allied front. A British stretcher bearer, William Collins, described what it was like to be shelled for the first time:
In that wood, to the entrance to that wood I heard the first shell burst above my head – it was a shrapnel shell – with a high-ish burst, white smoke and the bullets came down whistling like all the hobs of hell, as if a 1000 whistles had been turned on. The bullets, of course, were round but they had a little tick on them that made them whistle as they came through the air. That was my first shell. They came down like: . That was the noise the bullets made as they came down.
(Imperial War Museums)
Having made breakthroughs at several key points in the front, Kluck then improvised on the Schlieffen Plan, and instead of encircling Paris, he decided to move south and pursue the retreating enemy. Chasing the French Fifth Army, Kluck exposed his right flank to the garrison of Paris, a move revealed to the Allies by air reconnaissance. Moving to face this new attack on his flank, Kluck then left an unusually large gap between the German First and Second Armies, a gap that was quickly exploited by both the BEF and the French armies led by General Joseph Joffre (1852 to 1931). The bold curving arrows of the original Schlieffen Plan had now turned into a mess of multidirectional attacks, counterattacks, outflanking manoeuvres, and encirclements.
The German victories were costly in terms of time, material, and casualties, the BEF professional riflemen being particularly deadly in their fire. The French had lost around 300,000 men in just 14 days; the Germans had lost a similar amount. The French Army (and the BEF) had not collapsed, and, crucially for the prolongation of the war, a line was held between Nancy and Verdun.
The German commanders, although achieving their broad objective of ensuring the major battles would be on French soil, had greatly underestimated the fighting resistance of the enemy. Commanders in the field had also been distracted by strategic opportunities as they arose instead of concentrating on the overall plan of attack. This meant that the right wing of the German push into France was seriously weakened. The German plan was shown to be, like the French plan, wildly optimistic, since it "was based on Napoleonic élan and little else… took no account of defensive firepower" (Winter, 204).
Both sides were learning what 20th-century warfare was all about. The general rule of this particular war was firmly established in the first few weeks, although it was not heeded by the generals on either side for quite some time. Put simply, whoever attacked usually had to sustain the most casualties. Machine guns made short work of infantry. Old ideas die hard, but the French cavalry, for example, had learnt to their cost in that mad month of August the utter folly of charging the enemy in bright red trousers, plumed helmets, and glittering medals on their chests.
Another short, sharp lesson was that large troop movements required large logistical back-up, and this was not provided. The German soldiers marching into France that hot August quickly found themselves exhausted, hungry, and without sufficient ammunition.
Meanwhile, the whole point of the Schlieffen Plan to avoid two simultaneous fronts collapsed when Russia mobilised relatively quickly, reaching German territory in just 15 days. German command communications broke down badly. French and British forces rallied for a major counterattack in the First Battle of the Marne from 6 to 10 September, or what became known as the 'Miracle of the Marne'. The Germans decided to withdraw, and the front was pushed back, finally establishing itself along the Aisne River.
By the winter of 1914, and after a series of failed outflanking manoeuvres (known as 'the Race to the Sea') conducted by both sides, the Western Front stretched from Ypres near the Belgian coast to the Swiss border in the south. Both sides were obliged to build systems of trenches to better protect their troops from enemy fire. A long stalemate followed, with neither side ever making very much progress against the other over the next four years. This was exactly the situation the German generals had feared as Russia entered the war, and so, despite all the planning, they found themselves fighting on two massive fronts, a situation that ultimately cost them the war, even though Russia withdrew from WWI after the Bolshevik Revolution in 1917.