World War I

Table of Contents

Introduction & Top Questions
The outbreak of war
- Forces and resources of the combatant nations in 1914
- Technology of war in 1914
The initial stages of the war
- Initial strategies
  - The Schlieffen Plan
  - Eastern Front strategy, 1914
  - The strategy of the Western Allies, 1914
- The war in the west, 1914
  - The German invasion
  - The First Battle of the Marne
- The Eastern and other fronts, 1914
  - The war in the east, 1914
  - The Serbian campaign, 1914
  - The Turkish entry
  - The war at sea, 1914–15
  - The loss of the German colonies
The years of stalemate
- Rival strategies and the Dardanelles campaign, 1915–16
- The Western and Eastern fronts, 1915
  - The Western Front, 1915
  - The Eastern Front, 1915
- Other fronts, 1915–16
  - The Caucasus, 1914–16
  - Mesopotamia, 1914–April 1916
  - The Egyptian frontiers, 1915–July 1917
  - Italy and the Italian front, 1915–16
  - Serbia and the Salonika expedition, 1915–17
- Major developments in 1916
  - The Western Front, 1916
  - The Battle of Jutland
  - The Eastern Front, 1916
  - German strategy and the submarine war, 1916–January 1917
  - Peace moves and U.S. policy to February 1917
- Developments in 1917
  - The Western Front, January–May 1917
  - The U.S. entry into the war
  - The Russian revolutions and the Eastern Front, March 1917–March 1918
  - Greek affairs
  - Caporetto
  - Mesopotamia, summer 1916–winter 1917
  - Palestine, autumn 1917
  - The Western Front, June–December 1917
  - The Far East
  - Naval operations, 1917–18
  - Air warfare
  - Peace moves, March 1917–September 1918
The last offensives and the Allies’ victory
- The Western Front, March–September 1918
- Other developments in 1918
  - Czechs, Yugoslavs, and Poles
  - Eastern Europe and the Russian periphery, March–November 1918
  - The Balkan front, 1918
  - The Turkish fronts, 1918
  - Vittorio Veneto
  - The collapse of Austria-Hungary
- The final offensive on the Western Front
  - The end of the German war
  - The Armistice
- Killed, wounded, and missing

References & Edit History Quick Facts & Related Topics

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For Students

World War I

Key Facts of World War I

Archduke Franz Ferdinand and his wife, Sophie, duchess of Hohenberg

World War I Timeline

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General Pershing's troops moving into Mexico in 1917 during World War I.

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Written and fact-checked by The Information Architects of Encyclopaedia Britannica

News •

More military artifacts unearthed at Vancouver's PNE • May 2, 2025, 6:13 PM ET (CBC)

Princess Anne joins solemn ceremony in Turkey marking 110th anniversary of WWI battle • Apr. 25, 2025, 2:59 AM ET (AP)

Fort Benning takes back its old name, but to honor a different soldier • Apr. 16, 2025, 1:43 PM ET (AP)

Facts

Also Known As	Great War • First World War • WWI
Date	July 28, 1914 - November 11, 1918
Participants	Bulgaria • France • Germany • Italy • Japan • Ottoman Empire • Portugal • Russia • United Kingdom • United States

Did You Know?

When World War 1 began in the summer of 1914, most people assumed the war would be finished by Christmas.
The booming of the artillery at the Western front could sometimes be heard all the way back in Britain.
German and British soldiers called a truce on Christmas in 1914 and played a soccer game together.

Photos and Videos

Archduke Franz Ferdinand and his wife, Sophie, duchess of Hohenberg

Maxim machine gun

Somme; machine gun

Schlieffen Plan of 1905

World War I; German sailors

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World War I: torpedo boat

Women of World War I: Marie Curie, Mabel St. Clair Stobart, and Aileen Cole Stewart

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See how No Man's Land between World War I trenches led to the use of chemical weapons, tanks, and warplanes

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Learn how the Triple Entente and Triple Alliance evolved into the Allies and Central Powers in World War I

See All Videos and Images →

Topics

All Quiet on the Western Front U-boat zeppelin In Flanders Fields

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Timeline

Eastern Front

1914 - 1918

British Cavalry at the Battle of Mons

Battle of the Frontiers

August 4, 1914 - September 6, 1914

Battle of Morhange-Sarrebourg

August 20, 1914 - August 22, 1914

Western Front in World War I, 1914–18

Battle of Mons

August 23, 1914

Battle of Tannenberg

Battle of Tannenberg

August 26, 1914 - August 30, 1914

First Battle of the Marne

September 6, 1914 - September 12, 1914

First Battle of Ypres

October 19, 1914 - November 22, 1914

Battle of Tanga

November 2, 1914 - November 5, 1914

Falkland Islands

Battle of the Falkland Islands

December 8, 1914

Christmas Truce

Christmas Truce

December 24, 1914 - December 25, 1914

battle of Gallipoli

1915

Baltic and North seas and the English Channel

Battle of Dogger Bank

January 24, 1915

World War I: Allied troops on the Gallipoli Peninsula

Gallipoli Campaign

February 16, 1915 - January 9, 1916

The Dardanelles

naval operations in the Dardanelles Campaign

February 19, 1915 - March 18, 1915

gas masks at the Second Battle of Ypres

Second Battle of Ypres

April 22, 1915 - May 25, 1915

Battle of Verdun

Battle of Verdun

February 21, 1916 - December 18, 1916

Battle of Jutland

Battle of Jutland

May 31, 1916 - June 1, 1916

Somme; machine gun

First Battle of the Somme

July 1, 1916 - November 13, 1916

Battle of Arras

April 9, 1917 - May 17, 1917

Ypres, Belgium, 1918

Battle of Passchendaele

July 31, 1917 - November 6, 1917

Battle of Caporetto

October 24, 1917 - December 19, 1917

Battle of Gaza

November 1917

tank in the Battle of Cambrai

Battle of Cambrai

November 20, 1917 - December 8, 1917

German Prisoners at Belleau Wood

Battle of Belleau Wood

June 1, 1918 - June 26, 1918

Battle of Amiens

August 8, 1918 - August 11, 1918

John J. Pershing

Battle of Saint-Mihiel

September 12, 1918 - September 16, 1918

World War I: British army

Battle of Cambrai

September 27, 1918 - October 11, 1918

Battle of Mons

November 11, 1918

Read More: World War I Timeline

Key People

Sir Charles Monro

British army officer

Winston Churchill

Winston Churchill

prime minister of United Kingdom

Kemal Atatürk

Kemal Atatürk

president of Turkey

Woodrow Wilson

Woodrow Wilson

president of United States

David Lloyd George

David Lloyd George

prime minister of United Kingdom

Georges Clemenceau.

Georges Clemenceau

prime minister of France

Franz Joseph

Franz Joseph

emperor of Austria-Hungary

George S. Patton

George Patton

United States general

Herbert Hoover, 1928

Herbert Hoover

president of United States

Nicholas II

Nicholas II

tsar of Russia

William II.

William II

emperor of Germany

Jan Smuts.

Jan Smuts

South African statesman

Erich Ludendorff

Erich Ludendorff

German general

Nikola Pašić

prime minister of Serbia

Ferdinand Foch

Ferdinand Foch

marshal of France

Asquith

H.H. Asquith, 1st earl of Oxford and Asquith

prime minister of United Kingdom

John J. Pershing

John J. Pershing

United States general

Venizélos

Eleuthérios Venizélos

prime minister of Greece

Paul von Hindenburg

Paul von Hindenburg

German president

Sir Robert Borden

Sir Robert Borden

prime minister of Canada

Quiz

American infantry streaming through the captured town of Varennes, France, 1918.This place fell into the hands of the Americans on the first day of the Franco-American assault upon the Argonne-Champagne line. (World War I)

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Louis IX of France (St. Louis), stained glass window of Louis IX during the Crusades. (Unknown location.)

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Tecumseh. Battle of the Thames, Ontario, Canada, and the death of Tecumseh. Col. Richard M. Johnson with the Kentucky volunteers on left battle with Tecumseh and his Native troops. Native American Shawnee chief. North American indian. (See Notes)

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Louis IX of France (St. Louis), stained glass window of Louis IX during the Crusades. (Unknown location.)

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Photograph shows the ruins of the Cloth Hall after the Battle of Ypres during World War I in Ypres, West Flanders, Belgium, September 29, 1918.

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British troops in a trench on the Western front during World War I. One officer takes reports of the fighting over a field telephone while the officer on the left jots it down and issues new orders.

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Meeting of leaders in W.W.I, General Hindenburg, Kaiser William II, General Ludendorff examine maps during World War I in Germany.

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German machine gunners occupy a trench during World War I.

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General Pershing's troops moving into Mexico in 1917 during World War I.

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