Palestine Region in the Middle East between the River Jordan and the Mediterranean Sea. Part of the Ottoman empire until 1918, it became a British mandate under the terms of the Treaty of Sèvres (10 August 1920).

'Pals' battalions Groups of men from the same local community and/or profession who enlisted together in the British army during the First World War.

Pankhurst, Christabel (1880-1958) Radical women's suffrage campaigner and daughter of Emmeline Pankhurst, the founder of the Women's Social and Political Union (WSPU) in 1903.

Pankhurst, Emmeline (1858-1928) Radical women's suffrage campaigner and founder of the Women's Social and Political Union (WSPU) in 1903.

Paris peace conference Conference that ran from January to June 1919, attended by delegates from 37 nations, to decide post-war settlements with each of the defeated powers of the First World War. Most famous for producing the punitive peace with Germany, signed on 28 June and known as the Treaty of Versailles.

Passchendaele Village NE of the Belgian town of Ypres, whose name is often used to denote the 3rd Battle of Ypres (July-November 1917). Canadian troops seized the village on 6 November, by which time some 250,000 Allied and probably an even higher number of German troops had been killed.

'Peace programme' Also known as the 'Fourteen Points', this liberal and democratic blueprint for post-war Europe was first announced by US president Woodrow Wilson on 8 January 1918. It advocated territorial boundaries based on principles of national self-determination, an end to secret diplomacy, freedom of trade and a reduction of naval armaments.

Pensions, Ministry of Created by the new Lloyd George coalition government in December 1916.

Péronne Town in NE France on the River Somme. Captured by Germany during the Ludendorff offensive in the spring of 1918; recaptured by Australian troops on 31 August 1918.

Pershing, General John (1860-1948) Appointed to command the American Expeditionary Force in May 1917, he aroused Allied hostility - particularly from the French prime minister, Clemenceau - for his unbending refusal to deploy American troops in large numbers on the Western Front until a very late stage in the war. The first major American offensive did not take place until the attack on the St Mihiel salient in mid-September 1918.

Persia Former name (until 1935) of Iran. The unstable Persian kingdom, subject to strong Anglo-Russian commercial rivalry before 1914, remained neutral during the First World War but was the site of a number of skirmishes between the Allies and the Central Powers. It was occupied by both British and Russian forces towards the end of the war - they eventually withdrew in, respectively, 1921 and 1925.

Piave, River River in NE Italy, rising near the border of Austria. It was the main line of Italian defence during the First World War, towards which Italian forces retreated after defeat at the Battle of Caporetto (24 October-12 November 1917).

Picquet Also spelled 'picket'. A stand-alone guard post or small detachment of troops placed in advance of a position to give early warning of attack.

Poincaré, Raymond (1860-1934) Five-time French prime minister and president of the French Republic, 1913-20. Appointed his former enemy Georges Clemenceau as prime minister in 1917. Both men were conservative nationalists, strongly opposed to a negotiated peace with Germany.

Poison gas Principal chemical weapon used by both sides during the First World War. First used on a large scale when the Germans attacked French and Canadian troops with chlorine gas at the 2nd Battle of Ypres (April 1915). Increasingly lethal agents such as phosgene, hydrogen cyanide and mustard gas were deployed at later stages in the conflict, but their deadly effect was countered by the introduction of respirators ('gas masks') and other anti-gas measures. A total of 124,000 tons of poison gas were dropped during the First World War, causing 1.3 million casualties but just 91,000 deaths.

Poperinghe Town in W Flanders, 12 miles west of Ypres.

Princip, Gavrilo (1894-1918) Bosnian-Serb terrorist. Assassinated the heir to the Habsburg throne, Archduke Franz Ferdinand, and his wife on 28 June 1914 in Sarajevo.

'Prohibited areas' Term used to describe areas of Britain that were designated off limits to 'enemy aliens' and other non-military personnel during the First World War.

Provisional Government Interim government set up in Russia after the abdication of Tsar Nicholas II during the March 1917 revolution. It was led from July 1917 by Alexander Kerensky and continued to support Russia's participation in the war against the Central Powers. The Provisional Government was overthrown in the Bolshevik coup of November 1917.

Przemysl Habsburg fortress town in the province of Galicia. Captured by Russian forces in March 1915, but promptly recaptured by Austro-German forces in early June of the same year.