The Battle of the Frontiers (, , ) comprised battles fought along the eastern frontier of France and in southern Belgium, shortly after the outbreak of the First World War. The battles resolved the military strategies of the French Chief of Staff General Joseph Joffre with Plan XVII and an offensive adaptation of the German deployment plan by Helmuth von Moltke the Younger. The German concentration on the right (northern) flank, was to wheel through Belgium and attack the French in the rear. The German advance was delayed by the movement of the French Fifth Army (General Charles Lanrezac) towards the north-west to intercept them and the presence of the British Expeditionary Force (BEF) on the French left. The Franco-British troops were driven back by the Germans, who were able to invade northern France. French and British rearguard actions delayed the Germans, allowing the French time to transfer forces on the eastern frontier to the west to defend Paris, culminating in the First Battle of the Marne. Background Belgian plans Belgian military planning assumed that other powers would assist the Belgian Army to eject an invader and a formal alliance between France and Britain was not solidified by a potential German invasion, despite the Anglo-French Entente (1904). The Belgians judged that the British attitude towards their country had changed and that Belgium had come to be seen as a British protectorate. A General Staff was formed in 1910 but the , Lieutenant-Général Harry Jungbluth was retired on 30 June 1912 and not replaced by Lieutenant-General Chevalier de Selliers de Moranville until May 1914. Moranville began planning for the concentration of the army and met Belgian railway officials on 29 July. The Belgian army was to be massed in central Belgium, in front of the National redoubt of Belgium, ready to face any border, while the Fortified Position of Liège and Fortified Position of Namur were left to secure the frontiers. On mobilisation, the King became Commander-in-Chief and chose where the army was to concentrate. Amid the disruption of the new rearmament plan, disorganised and poorly trained Belgian soldiers would benefit from a central position to delay contact with an invader but it would also need fortifications for defence, which were on the frontier. A school of thought wanted a return to a frontier deployment, in line with French theories of the offensive. Belgian plans became a compromise, in which the