On this day in 1914, the second and third of what will be four "Battles of the Frontiers" fought between German and Allied forces on the Western Front during a four-day period in August 1914 begin near Ardennes and Charleroi in northern France.
During the first month of the Great War, with Germany advancing on France through Belgium, cutting a wide swath of violence on its way, French Commander in Chief Joseph Joffre pushed his 1st and 2nd Armies into the provinces of Alsace and Lorraine—forfeited to Germany after the Franco-Prussian War in 1871—against the German left wing. Joffre left the French 5th Army to counter the German right flank, which was swinging down north of the Meuse River, and sent his 3rd and 4th Armies to attack in the forests of Ardennes, where French army headquarters believed the enemy was relatively weak. Though German forces entered and occupied the Belgian capital city, Brussels, on August 20, French morale was strong, and Joffre remarked to his minister of war, Adolphe Messimy, that night: "There is reason to await with confidence the development of operations."
In fact, the German 4th and 5th Armies were pushing into the Ardennes as well, and on the foggy morning of August 21, French and German troops clashed in the second of four bloody confrontations that would collectively become known as the Battles of the Frontiers. (The first had occurred the day before, in Lorraine, when the French 1st and 2nd Armies were battered by the Germans at Sarrebourg and Morhange and forced to retreat.) At Ardennes, the French threw themselves forward with bayonets in a classic offensive maneuver—in accordance with their Plan 17 strategy, the French were convinced their glorious élan, or spirit, would carry them inexorably to victory. Instead, they came face to face with the superior artillery and entrenched machine guns of the Germans, and were brutally mown down in great numbers.
On the same day, August 21, the French 5th Army, commanded by General Charles Lanrezac clashed with General Karl von Bulow's 2nd German Army in the Battle of Charleroi, located to the north near the junction of the Sambre and Meuse rivers. The 5th Army, due to be supported by the newly arrived 100,000 soldiers of the British Expeditionary Force (BEF)—the largest number the tiny, professionally trained British army could send at the beginning of the war—instead had to fight alone, as a British delay and poor relations between Lanrezac and the BEF's commander, Sir John French, resulted in the British and French fighting two separate battles simultaneously—the Battle of Charleroi and the Battle of Mons, the fourth of the Battles of the Frontiers, which began on August 23—instead of fighting together as planned, to the detriment of both armies.
Over the course of the next three days, French, German and British forces would confront the strength of modern firepower for the first time, and all were shocked and devastated by its effects. In terms of numbers engaged and number of losses suffered over a comparable period of combat, the Battles of the Frontiers would remain the greatest struggles of World War I. More importantly, as a result of its convincing defeat of the French forces over those four days, Germany began consolidating its eventual hold on Belgium and northern France, which would give it control of the majority of the industrial power of both nations—coal, iron ore, factories, railroads and rivers—and give it the confidence to pursue its goal of victory to the bitter end.