The First World War

by Hew Strachan

which their army had been thrown by mobilisation in the Franco-Prussian war of 1870. They managed it so well that in 1914 they mobilised ahead of the Germans. Second, they had to deploy their forces to allow them to concentrate to either north or east, depending on where the main weight of the German attack came. Plan 17, the final version of France’s war plan, posted ten corps on the eastern frontier and five on the Belgian, with a further six behind Verdun ready to go in either direction. Formally speaking, Plan 17 made no provision for the British Expeditionary Force, but in the years before the war the expectation had developed that its two corps would be added to and extend the French front facing Belgium. The third task was to provide for advance guards to make contact with the enemy and identify the thrust of the attack. This was where things came unstuck. On 1 August France mobilised in support of its Russian ally, and on 3 August Germany declared war on France. Three days later Sordet’s cavalry corps set off into Belgium, following the line of the Meuse to within nine miles of Liege. It covered nearly forty miles a day, giving the horses no rest on the metalled roads, and getting through 15,000 horseshoes by 10 August. The cavalry continued the hectic pace over the next five days, ranging through the Ardennes and as far west as Charleroi. Sordet found no evidence that the Germans had come west of the Meuse. Joffre’s expectations