UPSC Mains Notes 2026 | GS Paper I | Page 27 – First World War (1914–1918) | Premium Complete Study Notes

 

Page 27 – First World War (1914–1918)

Introduction

The First World War (1914–1918) was the first global conflict involving major European powers and their colonies. More than 30 nations participated in the war, making it one of the most destructive conflicts in human history. The war transformed international politics, destroyed old empires, and laid the foundation for the Second World War.

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Learning Objectives

• Understand the political situation in Europe before 1914.
• Analyse the long-term and immediate causes of the First World War.
• Examine the system of alliances and European power politics.
• Prepare analytical notes for UPSC Prelims and GS Paper I Mains.

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Europe Before 1914

During the late nineteenth and early twentieth centuries, Europe witnessed intense competition among major powers. Industrialisation, imperial expansion, military rivalry and nationalism increased tensions across the continent.

Major European Powers

• Britain
• France
• Germany
• Austria-Hungary
• Russia
• Italy
• Ottoman Empire

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Main Causes of the First World War

1. Militarism

European countries rapidly expanded their armies and navies. Germany and Britain competed to build powerful naval fleets, while continental powers increased military expenditure and prepared for large-scale war.

2. Alliance System

Europe became divided into two rival military alliances.

Alliance	Members
Triple Alliance	Germany, Austria-Hungary, Italy
Triple Entente	Britain, France, Russia

These alliances meant that a conflict between two countries could quickly involve many others.

3. Imperialism

European powers competed for colonies in Asia and Africa. Rivalries over markets, raw materials and overseas territories increased international tensions.

4. Nationalism

Nationalist movements strengthened unity within nations but also created conflicts among different ethnic groups, particularly in the Balkans. Serbia supported Slavic nationalism, which challenged the authority of Austria-Hungary.

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Immediate Cause

On 28 June 1914, Archduke Franz Ferdinand, the heir to the Austro-Hungarian throne, was assassinated at Sarajevo by Gavrilo Princip, a Bosnian Serb nationalist.

Austria-Hungary declared war on Serbia on 28 July 1914. Because of the alliance system, the conflict rapidly expanded into a world war.

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Flowchart – Causes of the First World War

Militarism
      │
Alliance System
      │
Imperialism
      │
Nationalism
      │
Assassination at Sarajevo
      │
Austria vs Serbia
      │
First World War (1914)

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UPSC Value Addition

• War Period: 1914–1918
• Immediate Cause: Assassination of Archduke Franz Ferdinand
• Place: Sarajevo (Bosnia)
• Assassin: Gavrilo Princip
• Triple Alliance: Germany, Austria-Hungary, Italy
• Triple Entente: Britain, France, Russia
• Key Concept: M.A.I.N. = Militarism, Alliances, Imperialism, Nationalism

Part 2 – Major Events, Important Battles & Course of the First World War

Beginning of the War (1914)

Following the assassination of Archduke Franz Ferdinand, Austria-Hungary declared war on Serbia on 28 July 1914. Due to the alliance system, Germany, Russia, France and Britain soon entered the conflict, turning a regional dispute into a global war.

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Major Fronts of the War

1. Western Front

• Fought mainly in France and Belgium.
• Germany fought against Britain, France and later the United States.
• Known for trench warfare and prolonged stalemate.

2. Eastern Front

• Germany and Austria-Hungary fought against Russia.
• The front covered a much larger geographical area.
• Germany achieved several important victories.

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Trench Warfare

The Western Front became famous for trench warfare. Soldiers lived in long, narrow trenches protected by barbed wire and machine guns. Fighting was slow and extremely costly, with very limited territorial gains despite heavy casualties.

Features

• Deep defensive trenches.
• Machine guns and heavy artillery.
• Poison gas used as a new weapon.
• Large loss of life with little movement of front lines.

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Major Battles

Battle	Year	Importance
First Battle of the Marne	1914	Stopped the German advance towards Paris.
Battle of Verdun	1916	One of the longest and bloodiest battles of the war.
Battle of the Somme	1916	Massive casualties and first large-scale use of tanks by Britain.
Battle of Jutland	1916	Largest naval battle between Britain and Germany.

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Entry of the United States (1917)

In 1917, the United States entered the war on the side of the Allied Powers. German unrestricted submarine warfare and the Zimmermann Telegram were major reasons for American involvement. Fresh American troops and resources significantly strengthened the Allies.

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Russian Revolution and Withdrawal

The Russian Revolution of 1917 overthrew the Tsarist regime. The new Bolshevik government signed the Treaty of Brest-Litovsk (1918) with Germany and withdrew Russia from the war.

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End of the War

The Allied Powers launched successful offensives during 1918. Germany's military position weakened, and on 11 November 1918, an armistice was signed, bringing the fighting to an end.

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Timeline

Year	Event
1914	World War I began.
1914	First Battle of the Marne.
1916	Battle of Verdun.
1916	Battle of the Somme.
1917	United States entered the war.
1917	Russian Revolution.
1918	Treaty of Brest-Litovsk.
11 November 1918	Armistice signed.

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UPSC Value Addition

• Western Front: Trench warfare and stalemate.
• Eastern Front: Large-scale battles between Germany and Russia.
• Important Battles: Marne, Verdun, Somme and Jutland.
• USA entered: 1917.
• Russia withdrew: Treaty of Brest-Litovsk (1918).
• War ended: Armistice on 11 November 1918.

Part 3 – Treaty of Versailles, Consequences & Global Impact

Treaty of Versailles (1919)

The Treaty of Versailles was signed on 28 June 1919 between Germany and the Allied Powers. It officially ended the First World War. The treaty imposed severe political, military, territorial and economic conditions on Germany, creating widespread resentment that later contributed to the rise of Adolf Hitler and the Second World War.

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Major Provisions of the Treaty

Provision	Description
War Guilt Clause	Germany accepted responsibility for causing the war (Article 231).
Reparations	Germany was required to pay heavy compensation to the Allied Powers.
Territorial Losses	Germany lost Alsace-Lorraine, overseas colonies and several European territories.
Military Restrictions	The German Army was reduced, compulsory military service was abolished, and the navy and air force were severely restricted.
League of Nations	The treaty established the League of Nations to promote international peace.

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League of Nations

The League of Nations was founded in 1920 to prevent future wars through collective security, peaceful settlement of disputes and international cooperation.

Objectives

• Maintain international peace and security.
• Promote peaceful resolution of disputes.
• Encourage disarmament.
• Improve international cooperation.

Reasons for Failure

• The United States did not join.
• The League had no permanent military force.
• Major powers ignored League decisions.
• Failure to stop aggression by Japan, Italy and Germany.

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Political Consequences

• Collapse of the German, Austro-Hungarian, Ottoman and Russian Empires.
• Creation of new nation-states such as Poland, Czechoslovakia and Yugoslavia.
• Expansion of democratic governments in several countries.
• Rise of revolutionary movements.

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Economic Consequences

• Severe economic destruction across Europe.
• Massive war debts and inflation.
• Industrial and agricultural losses.
• Financial instability that contributed to later economic crises.

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Social Consequences

• Millions of soldiers and civilians lost their lives.
• Large numbers of refugees and displaced people.
• Greater participation of women in the workforce.
• Rapid social and political changes across Europe.

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Impact on International Relations

• Shift in global political power.
• Decline of European dominance.
• Rise of the United States as a major world power.
• Growth of communist influence after the Russian Revolution.
• Development of new diplomatic institutions.

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How the First World War Led to the Second World War

First World War
        │
Treaty of Versailles
        │
German Humiliation
        │
Economic Crisis
        │
Rise of Hitler & Nazism
        │
Aggressive Expansion
        │
Second World War (1939)

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UPSC Analytical Perspective

Many historians argue that the Treaty of Versailles created a "victor's peace" rather than a "just peace." The harsh conditions imposed on Germany generated political instability, economic hardship and nationalist resentment, making Europe vulnerable to another major conflict within two decades.

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UPSC Value Addition

• Treaty Signed: 28 June 1919
• League of Nations Founded: 1920
• War Guilt Clause: Article 231
• Collapsed Empires: German, Austro-Hungarian, Ottoman and Russian
• Major Link: Treaty of Versailles → Rise of Nazism → Second World War
• Exam Tip: In Mains answers, connect the First World War with nationalism, imperialism, the Russian Revolution and the emergence of fascism and Nazism.

Part 4 – UPSC Mains Questions & Premium Model Answers

Why is the First World War Important for UPSC?

The First World War transformed global politics, ended old empires, reshaped international relations and created conditions that eventually led to the Second World War. UPSC frequently links this topic with nationalism, imperialism, the Russian Revolution, the Treaty of Versailles and the League of Nations.

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UPSC Mains Question 1 (10 Marks | 150 Words)

What were the major causes of the First World War?

Model Answer

Introduction

The First World War began in 1914 due to a combination of long-term political rivalries and the immediate crisis following the assassination of Archduke Franz Ferdinand.

Main Causes

• Militarism and the arms race.
• Alliance System dividing Europe into rival camps.
• Imperialist competition for colonies.
• Aggressive nationalism, especially in the Balkans.
• Assassination of Archduke Franz Ferdinand at Sarajevo.

Conclusion

The war was not caused by a single event but by the interaction of military rivalry, alliances, imperial ambitions and nationalism.

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UPSC Mains Question 2 (15 Marks | 250 Words)

Analyse the significance of the Treaty of Versailles in shaping twentieth-century world politics.

Model Answer

Introduction

The Treaty of Versailles (1919) officially ended the First World War but imposed severe conditions on Germany, creating long-term political instability.

Major Provisions

• War Guilt Clause (Article 231).
• Heavy reparations.
• Territorial losses.
• Military restrictions.
• Creation of the League of Nations.

Impact

• German resentment and political instability.
• Economic hardship and hyperinflation.
• Rise of Adolf Hitler and Nazism.
• Failure of collective security.
• Path towards the Second World War.

Conclusion

The Treaty created peace in the short term but failed to establish lasting international stability.

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UPSC Mains Question 3 (15 Marks | 250 Words)

Discuss the achievements and failures of the League of Nations.

Model Answer

Achievements

• Promoted peaceful settlement of disputes.
• Supported humanitarian and health initiatives.
• Encouraged international cooperation.

Failures

• United States remained outside the League.
• No permanent military force.
• Unable to stop aggression by Japan, Italy and Germany.
• Weak enforcement of decisions.

Conclusion

Despite noble objectives, structural weaknesses prevented the League from maintaining global peace.

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UPSC Mains Question 4 (20 Marks | 250 Words)

"The First World War was the turning point in modern world history." Critically examine.

Points to Include

• Collapse of four major empires.
• Emergence of new nation-states.
• Rise of the United States as a global power.
• Russian Revolution and spread of communism.
• Growth of fascism and Nazism.
• Creation and failure of the League of Nations.
• Foundation for the Second World War.

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Value Addition for UPSC

Important Personalities

• Archduke Franz Ferdinand
• Kaiser Wilhelm II
• Woodrow Wilson
• David Lloyd George
• Georges Clemenceau
• Vladimir Lenin

Important Terms

• Militarism
• Alliance System
• Imperialism
• Nationalism
• Trench Warfare
• League of Nations
• Treaty of Versailles
• War Guilt Clause

Important Dates

Year	Event
28 June 1914	Assassination of Archduke Franz Ferdinand
28 July 1914	Austria-Hungary declared war on Serbia
1917	United States entered the war
1917	Russian Revolution
11 November 1918	Armistice signed
28 June 1919	Treaty of Versailles

Examiner's Expectations

• Differentiate between long-term and immediate causes.
• Use headings such as Causes, Course, Consequences and Evaluation.
• Support answers with important dates and examples.
• Link the First World War with the Russian Revolution, the Treaty of Versailles, the League of Nations and the origins of the Second World War.
• Conclude with a balanced historical assessment rather than only listing facts.

Part 5 – UPSC Prelims MCQs, PYQ Practice & Exam Booster

UPSC Prelims Practice MCQs

MCQ 1

The immediate cause of the First World War was:

A. German invasion of Belgium
B. Russian Revolution
C. Assassination of Archduke Franz Ferdinand
D. Treaty of Versailles

Answer: C. Assassination of Archduke Franz Ferdinand

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MCQ 2

Which of the following countries were members of the Triple Entente?

A. Germany, Italy, Austria-Hungary
B. Britain, France, Russia
C. Germany, Russia, Italy
D. France, Germany, Britain

Answer: B. Britain, France, Russia

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MCQ 3

The Treaty of Versailles was signed in:

A. 1918
B. 1919
C. 1920
D. 1921

Answer: B. 1919

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MCQ 4

The League of Nations was established primarily to:

A. Promote colonial expansion
B. Prevent future wars through collective security
C. Increase military alliances
D. Divide Europe into spheres of influence

Answer: B. Prevent future wars through collective security

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MCQ 5

Which treaty led to Russia's withdrawal from the First World War?

A. Treaty of Paris
B. Treaty of Brest-Litovsk
C. Treaty of Tordesillas
D. Treaty of Utrecht

Answer: B. Treaty of Brest-Litovsk

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Advanced Statement-Based Question

Consider the following statements:

1. The First World War lasted from 1914 to 1918.
2. The United States entered the war in 1917.
3. The League of Nations successfully prevented the Second World War.

Which of the statements given above are correct?

A. 1 and 2 only
B. 2 and 3 only
C. 1 and 3 only
D. 1, 2 and 3

Answer: A. 1 and 2 only

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Assertion and Reason

Assertion (A): The Treaty of Versailles created long-term resentment in Germany.

Reason (R): Germany was forced to accept the War Guilt Clause and pay heavy reparations.

Answer: Both A and R are true, and R is the correct explanation of A.

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Previous Year UPSC Theme

UPSC generally asks analytical questions on the causes, consequences and global impact of the First World War. The topic is often linked with the Russian Revolution, the Treaty of Versailles, the League of Nations and the emergence of the Second World War.

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One-Minute Revision Table

Topic	Key Point
War Period	1914–1918
Immediate Cause	Assassination of Archduke Franz Ferdinand
Triple Alliance	Germany, Austria-Hungary, Italy
Triple Entente	Britain, France, Russia
USA Entered	1917
Russia Withdrew	Treaty of Brest-Litovsk (1918)
War Ended	11 November 1918
Treaty of Versailles	28 June 1919

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Common UPSC Mistakes to Avoid

• Do not confuse the causes of the war with the immediate trigger.
• Remember that the League of Nations was created after the war, not before it.
• Know the difference between the Triple Alliance and the Triple Entente.
• Do not confuse the Armistice (1918) with the Treaty of Versailles (1919).
• Always connect the First World War with the rise of Fascism, Nazism and the Second World War.

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Exam Booster

Golden Revision Formula:

M.A.I.N.

M – Militarism
A – Alliance System
I – Imperialism
N – Nationalism

Timeline:

1914 → War Begins → 1917 USA Enters → 1917 Russian Revolution → 1918 Armistice → 1919 Treaty of Versailles → 1920 League of Nations

Part 6 – Premium Revision Module

Mind Map

European Rivalries
        │
────────────────────────
│      │      │      │
Militarism  Alliances
Imperialism Nationalism
        │
Assassination of
Archduke Franz Ferdinand
(28 June 1914)
        │
Austria declares war
on Serbia
        │
Alliance System Activated
        │
First World War
(1914–1918)
        │
────────┼────────
│                │
Millions Dead    Economic Destruction
│                │
Collapse of Empires
│
Treaty of Versailles (1919)
│
League of Nations
│
Rise of Fascism & Nazism
│
Second World War

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Complete Timeline

Year	Event
28 June 1914	Assassination of Archduke Franz Ferdinand
28 July 1914	Austria declared war on Serbia
1914	Battle of the Marne
1916	Battle of Verdun
1916	Battle of the Somme
1917	United States entered the war
1917	Russian Revolution
1918	Treaty of Brest-Litovsk
11 November 1918	Armistice signed
28 June 1919	Treaty of Versailles
1920	League of Nations established

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Memory Mnemonics

M.A.I.N.

• M – Militarism
• A – Alliance System
• I – Imperialism
• N – Nationalism

Battle Sequence:

M → V → S

• Marne
• Verdun
• Somme

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30-Second Revision

• War Period: 1914–1918.
• Immediate cause: Assassination of Archduke Franz Ferdinand.
• Main causes: Militarism, Alliances, Imperialism and Nationalism.
• USA entered the war in 1917.
• Russia withdrew after the Treaty of Brest-Litovsk (1918).
• Armistice signed on 11 November 1918.
• Treaty of Versailles signed on 28 June 1919.
• League of Nations established in 1920.

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5-Minute UPSC Revision

• Background of European rivalries.
• Triple Alliance and Triple Entente.
• Immediate trigger at Sarajevo.
• Major battles and trench warfare.
• Entry of the United States.
• Russian Revolution and withdrawal.
• Treaty of Versailles and its provisions.
• League of Nations and reasons for failure.
• Political, economic and social consequences.
• Connection between World War I and World War II.

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UPSC Interview Corner

Question: Why is the First World War considered a turning point in modern history?

Model Answer: The war ended four major empires, redrew the political map of Europe, accelerated the rise of the United States and the Soviet Union, created the League of Nations, and generated conditions that contributed to the rise of fascism, Nazism and the Second World War.

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Chapter Summary

The First World War was a global conflict driven by militarism, alliance politics, imperial rivalry and nationalism. The assassination at Sarajevo triggered a chain reaction that drew major powers into war. The conflict caused immense human and economic losses, ended several empires and reshaped world politics. The Treaty of Versailles and the weaknesses of the League of Nations failed to secure lasting peace, making the First World War a crucial link in understanding the origins of the Second World War.

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Exam Ready Notes

• Remember the acronym M.A.I.N. for the causes of the war.
• Differentiate between the Armistice (1918) and the Treaty of Versailles (1919).
• Relate the First World War to the Russian Revolution, the League of Nations and the emergence of Fascism and Nazism.
• Use timelines, flowcharts and analytical points in Mains answers to improve presentation and scoring.