The First World War began in August 1914 as a conflict between European powers, but soon engulfed the world, resulting in millions of deaths before the Armistice of 11 November 1918. It was one of the defining events of the 20th century.



Economic competition, national ambitions, colonial rivalries and the advancement in military technology amongst the great European empires led to the outbreak of the First World War. The rise of Germany’s military and industrial might upset the balance of power in Europe and by 1914 the major European nations were split into opposing alliances. The Triple Entente included Britain, France and Russia, later joined by Italy and the United States. The Central Powers included Germany and Austria-Hungary, later to be joined by the Ottoman Empire.

© IWM (Q 70169) Still from film of the Battle of the Somme. Sequence 31 ('The Attack') - second stage.

Outbreak of War

The assassination of Archduke Franz Ferdinand, the heir to the Austrian throne, on 28 June 1914 in Sarajevo, set in motion a chain of events that plunged the world into a war that lasted more than four years. Austria-Hungary declared war on Serbia which prompted the Russians to mobilise in support of the Serbs. This was followed by a German declaration of war on Russia. When the German demand for right of passage through Belgium was rejected, Germany declared war on France and invaded Belgium. This violation of Belgian neutrality brought Britain into the conflict.

By the end of 1914, trench warfare had emerged on the Western Front in France and Flanders, with defences stretching in an unbroken line from the Alps to the North Sea. Hundreds of thousands of men perished in attempts to break through the opposing lines. At the same time, Germany and Austria-Hungary fought Russia on the Eastern Front, until the Russian revolution of 1917 effectively took Russia out of the war. In the spring of 1917, the United States entered the war on the side of the Entente.

Global War

As the European powers fought in Europe, their Dominions, colonies and imperial possessions, along with their allies in other parts of the world, were also drawn into the conflict. Attempts to defeat the Central Powers away from the Western Front included the landings on Gallipoli, where the Allies were successfully defeated by the Ottomans in 1915 suffering heavy losses, and the Salonika campaign in Greece and Macedonia. Britain's Royal Navy established a blockade of Germany, which eventually put considerable pressure on the German home front, and Germany responded with submarine warfare.

In Egypt and Palestine, the campaign began around the Suez Canal and eventually ended with the advance of British-led forces all the way up to Jerusalem and Aleppo. In Mesopotamia and Persia, the protection of British oil interests opened another bloody front ending with the occupation of Baghdad and the creation of Iraq. Africa saw some of the earliest fighting in the war between colonial troops of France, Britain and Germany, and campaigns continued across the continent, particularly in East Africa. There was also fighting in minor theatres such as Afghanistan, the Pacific, and China.


The Armistice of 11 November 1918 ended the fighting on the Western Front. It was followed by the signing of peace treaties including the Treaty of Versailles with Germany on 28 June 1919. The war had far-reaching political, social and economic effects, including the dissolution of the German, Austro-Hungarian, Ottoman and Russian Empires. More than one million people serving with British Empire forces lost their lives, while in total the war caused the deaths of nearly 13 million military personnel, with more than 21 million wounded. Millions of civilians were impacted by the war and its aftermath.

Cemeteries & Memorials

What was then called the Imperial War Graves Commission was formally established in 1917, during the First World War. Today, the CWGC commemorates all those men and women who lost their lives while serving with the forces of the British Empire across the globe. We care for graves in our war cemeteries and other burial grounds, many of which lie on the former battlefields. The names of those with no known grave are listed on our Memorials to the Missing, including the Menin Gate in Ypres (Ieper) and the Thiepval Memorial on the Somme. Many also honour particular battles or forces, and several are particularly significant for Commonwealth countries.