The Battle of Frontiers was several battles in the beginning of the World War I. They occurred in the eastern parts of France and southern parts of Belgium. These battles were led by General Joseph Joffre (France) and Helmuth von Moltke the Younger (Germany). The Germans had a plan to move through Belgium and attack French forces from the rear. This plan was delayed because of General Charles Lanrezac's movement and BEF (British Expeditionary Force). French and British forces were driven back by the German army. However, French and British forces slowed the progress of German forces, so they had time to retreat and prepare for defending Paris. Due to the Germans offensive, the First Battle of the Marne was a result.
During the Battle of the Frontiers, the French army was defeated. The First and Second army were back on their start on 20 August. Third and Fourth army were defeated between 21 and 23 August the same year. At that time, the Fifth army was defeated on the Sambre and they had to retreat. While French armies were in retreat, they were destroying railways and they wanted to kill as many German soldiers as possible, in order to weaken the German forces and prepare them for future attack.
The strength of the French army was 1.250.000 soldiers. The British had 70.000 soldiers and Belgium had on its disposal 117.000 soldiers. They lost: 329.000 (France between 6 August and 5 September); 29.597 (Britain between August and September) and 4.500 (Belgium). On the other side, Germany had 1.300.000 soldiers and they lost 206.515 (August) and 99.079 (1-10 September).