Field Marshal Sir Archibald Armar Montgomery-Massingberd, (6 December 1871 – 13 October 1947), known as Archibald Armar Montgomery until October 1926, was a senior British Army officer who served as Chief of the Imperial General Staff (CIGS) from 1933 to 1936. He served in the Second Boer War and in the First World War, and later was the driving force behind the formation of a permanent "Mobile Division", the fore-runner of the 1st Armoured Division. Military career His father was Hugh de Fellenberg Montgomery, a landowner and Ulster Unionist politician, and his mother was Mary Sophia Juliana May Montgomery (née Maude). The young Montgomery was educated at Charterhouse and at the Royal Military Academy, Woolwich, and then was commissioned a second lieutenant into the Royal Field Artillery on 4 November 1891. He was posted to a field battery in India in 1892 and became a lieutenant on 4 November 1894. He served with the Royal Field Artillery during the Second Boer War and took part in the Battle of Magersfontein and the Battle of Paardeberg. Having been promoted to captain on 8 March 1900, he was mentioned in despatches on 4 September 1901. He stayed in South Africa throughout the war, which ended with the Peace of Vereeniging on 31 May 1902, and returned home on the which arrived at Southampton in late October 1902. After the war Montgomery served as a battery captain at Bulford Camp before attending Staff College, Camberley from 1905 to 1906. He became a staff captain at the Inspectorate of Horse and Field Artillery in 1907 and a staff officer at Aldershot Command in 1908. Promoted to major on 5 June 1909, he was appointed a general staff officer at the Indian Army Staff College at Quetta in India on 9 February 1912. At the outbreak of the First World War in July 1914 Montgomery was appointed a general staff officer to the British Expeditionary Force (BEF) in France. He was appointed Chief of Staff at IV Corps in France in October 1914. Promoted to lieutenant-colonel on 16 May 1915, he became Chief of Staff of Fourth Army of the BEF in February 1916, a role which, according to Field Marshal Sir Douglas Haig, from the planning for the Battle of the Somme in 1916 he carried out with "great ability and success". Promoted to the substantive rank of major-general on 1 January 1917, he