Ratings Ordinary seamen, holding neither commissioned nor warrant rank in the Royal Navy.

Rawlinson, Henry (1864-1925) Commander of the British Fourth Army at the Battle of the Somme (July-November 1916) and again during the Allied counter-offensive (July-November 1918).

Reconstruction, Ministry of Set up in August 1917 to plan the post-war rebuilding of British society. Headed by Christopher Addison, it was discontinued in June 1919.

'Red Baron' Nickname by which the most successful German pilot of the First World War, Manfred von Richthofen (1892-1918), was commonly known. He shot down 80 Allied aircraft before being killed in action by a Canadian pilot over France on 21 April 1918.

Regular army Term by which the pre-war volunteer British army was commonly known.

Remarque, Erich Maria (1898-1970) German-born US writer. Author of one of the most famous novels about the First World War, All Quiet on the Western Front (1929).

Reparations Under the Treaty of Varsailles, Germany was required to pay reparations (compensation) to the countries it had attacked. The severity of the reparations contributed to Germany's economic problems in the 1930s and contributed to the political crises that led to the Second World War.

Representation of the People Act Act passed in February 1918 that enfranchised for the first time - subject to certain residency qualifications - all men over the age of 21 and all women over the age of 30.

Rhineland Valuable industrial region of Germany around the River Rhine. Occupied by Allied troops at the end of the First World War (until 1930). Articles 42-44 of the Treaty of Versailles (28 June 1919) forbade Germany from stationing any military formations there.

Richthofen, Manfred von See 'Red Baron'.

Robertson, Sir William (1860-1933) Chief of staff in France in 1915. Chief of the Imperial General Staff, 1915-18, during which time he clashed on numerous occasions over British war policy with the prime minister, David Lloyd George.

Room 40 Room at Admiralty headquarters in London, in which British cryptographers unravelled German naval codes during the First World War.

Roosevelt, Theodore (1859-1919) US president, 1901-09. Arch-opponent of the USA's wartime president, Woodrow Wilson, and a strong critic of American neutrality between 1914 and 1917.

Royal Air Force (RAF) The world's first independent air force, created on 1 April 1918 out of an amalgamation of the Royal Flying Corps and the Royal Naval Air Service.

Royal Engineers Branch of the British army that undertakes engineering work such as the construction of fortifications, mines and bridges.

Royal Flying Corps (RFC) Formed as an army corps in May 1912 from the Royal Engineers Balloon Section. Discontinued on 1 April 1918 when it merged with the Royal Naval Air Service to become the Royal Air Force (RAF).

Royal Naval Air Service (RNAS) Previously the naval wing of the RFC, the RNAS was founded as a separate air branch for the Royal Navy on 1 July 1914. Discontinued on 1 April 1918 when it merged with the Royal Flying Corps to become the Royal Air Force (RAF).

Royal Naval Division (RND) Formed under Admiralty control in 1914 from 30,000 sailors for whom the Royal Navy had no ships. Saw service on the Western Front and in Gallipoli between 1914 and 1916. Control of the RND was transferred to the War Office in 1916, when it was re-named the 63rd (RN) Division.

Royal Naval Reserve (RNR) Created in 1859 to provide the Admiralty with a reserve of up to 30,000 merchant seamen and fishermen to be called on in times of national emergency.

Royal Naval Volunteer Reserve (RNVR) Founded in 1903 as a volunteer organisation for the Royal Navy. Composed of men from all professional backgrounds except merchant seamen and fishermen, who joined the RNR instead.

Ruhr Chief German coal-mining and industrial region, based in the valley of the River Ruhr in NW Germany. The industrial centre of the German war effort in the First World War; occupied by Belgian and French troops between 1923 and 1925, when Germany failed to keep up with its reparations payments.

Rupprecht, Crown Prince (1869-1955) Crown prince of Bavaria, whose military talents led to his appointment as commander of 'Army Group Prince Rupprecht' on the Western Front in August 1916. One of the first German military leaders to recognise that Germany's position was beyond repair after the Battle of Amiens (8-11 August 1918), he was also a strong critic of Ludendorff's conduct of the war.

Russell, Bertrand (1872-1970) British philosopher, mathematician and pacifist. A vociferous opponent of the First World War, Russell was active in both the Union of Democratic Control and the No-Conscription Fellowship. He was fined in June 1916 for publishing a leaflet supporting conscientious objection and eventually imprisoned for six months in February 1918 for publicly urging that Britain should take up Germany's offer of peace talks.

Russian civil war A series of civil wars in the territories of the former Russian empire (1918-21). The main one centred on a bitter struggle for control of the central Russian government between the Bolshevik 'Reds' and the counter-revolutionary 'Whites'. The situation was complicated by the presence of foreign troops from Britain, France, the USA and elsewhere and by the breakaway attempts of areas in the tsarist borderlands such as Poland and the Ukraine.