Under the command of Field Marshal Sir John French, the British Expeditionary Force (BEF) began to deploy to France within days of the declaration of war. The first encounter with the Germans came at Mons on 23 August 1914, after which the Allies began the Great Retreat, the BEF was involved in the Battle of Le Cateau. The BEF had a small role in halting the German advance at the First Battle of the Marne, before participating in the Aisne counter-offensive, in September which was followed by a period known as the "Race to the Sea" during which the BEF redeployed to Flanders. For the BEF, 1914 ended with "First Ypres" which marked the beginning of a long struggle for the Ypres Salient. British casualties in the fighting between 14 October and 30 November were 58,155 (7,960 dead, 29,562 wounded and 17,873 missing). It is often said that the pre-war professional army died at the First Battle of Ypres. The British Army had arrived in France with some 84,000 infantrymen. By the end of the battle, the BEF had suffered 86,237 casualties, mostly to the infantry.