Crossing the Channel in the early days of World War I, the British Expeditionary Force deployed in the fields of Belgium. Led by Sir John French, the BEF moved into position in front of Mons and formed a line along the Mons-Condé Canal, just to the left of the French Fifth Army. A fully professional force, the BEF dug in to await the advancing Germans who were sweeping through Belgium in accordance to the Schlieffen Plan. On August 22, after being defeated by the Germans, the commander of the Fifth Army, General Charles Lanrezac, asked French to hold his position along the canal for 24 hours while French fell back.
Agreeing, French instructed his two corps commanders, General Douglas Haig and General Horace Smith-Dorrien to prepare for the German onslaught. That same day, around 6:30 AM, the lead elements of General Alexander von Kluck's First Army began making contact with the British. The first skirmish occurred in the village of Casteau when C Squadron of the Royal Dragoon Guards encountered men from the German 2nd Kuirassiers. This fight saw Drummer Edward Thomas fire the first British shots of the war. Driving the Germans off, the British returned to their lines.
At 5:30 AM on August 23, French again met with Haig and Smith-Dorrien and told them to strengthen the line along the canal and to prepare the canal bridges for demolition. In the early morning mist and rain, the Germans began appearing on the BEF's 20-mile front in increasing numbers. Shortly before 9:00 AM, German guns were in position north of the canal and opened fire on the BEF's positions. This was followed by an eight-battalion assault by infantry from the IX Korps. Approaching the British lines Obourg and Nimy, this attack was met by heavy fire form the BEF's veteran infantry.
Decimating the German ranks, the British maintained a such a high rate of fire with their Lee-Enfield rifles that the attackers believed they were facing machine guns. As von Kluck's men arrived in greater numbers, the attacks intensified forcing the British to consider falling back. On the north edge of Mons, a bitter fight ensued between the Germans and the 4th Royal Fusiliers around a swing bridge. Left open by the British, the Germans were able to cross when Private August Neiemeier jumped in the canal and closed the bridge.
By noon, French was forced to order his men to begin falling back due to heavy pressure on his front and the appearance of the German 17th Division on his right flank. Around 2:00 PM, Mons was abandoned and elements of the BEF became engaged in rearguard actions along the line. In one situation a battalion of the Royal Munster Fusiliers held off nine German battalions and secured the safe withdrawal of their division. As night fell, the Germans halted their assault to reform their lines. With the pressure relieved, the BEF fell back to Le Cateau and Landrecies.