Europe in the 1930s: marching columns, mass rallies, and the shadow of another war gathering over the continent.

Premium Story

The Causes of the Second World War

Q: How did the Treaty of Versailles contribute to World War II?

Versailles did not make war inevitable, but it fed German resentment, weakened the Weimar Republic, and gave extremists a powerful grievance to exploit.

Trace the layered causes of WWII through Versailles, fascism, depression, appeasement, and the failure of collective security.

Start the story Explore Premium

11 chapters

Reading mode

Accessible gives a lighter overview. Deep Dive tells the fuller story.

Quick Answers

What caused the Second World War?

The Second World War did not begin in 1939. It was built across two decades through unresolved grievances, economic catastrophe, the rise of violent ideologies, and the systematic failure of the international order to stop determined aggressors.

At a glance

Date range: 1919 to 1939.
The causes of World War II built across two decades of grievance, dictatorship, economic crisis, expansion, and failed deterrence.
The Treaty of Versailles imposed punishing terms on Germany in 1919, generating lasting resentment that fuelled nationalist and extremist politics for two decades.
Economic catastrophe — hyperinflation in the early 1920s and the Great Depression after 1929 — repeatedly destabilised democratic governments and made authoritarian alternatives more attractive.

Common questions

What were the main causes of the Second World War?

The main causes included the Treaty of Versailles, the Great Depression, fascist and militarist expansion, appeasement, weak international enforcement, and Hitler's decision to attack Poland.

How did the Treaty of Versailles contribute to World War II?

did not make war inevitable, but it fed German resentment, weakened the Weimar Republic, and gave extremists a powerful grievance to exploit.

What was appeasement?

Appeasement was the British and French policy of making concessions to avoid war, especially toward Hitler. It reached its peak at in 1938 and failed to stop Nazi expansion.

When did World War II begin?

World War II began in Europe on 1 September 1939 when Germany invaded Poland. Britain and France declared war on Germany two days later.

Context

Introduction

Overview

The war that began in 1939 took shape over two decades. Unsettled grievances after the First World War, economic collapse and violent political movements weakened the international order. Aggression met repeated failures of deterrence until the invasion of Poland made a wider European war unavoidable.

What you'll learn: You will trace the layered causes of the Second World War, from the flawed peace of 1919 through economic collapse, the rise of fascism, the failure of collective security, and the policy of appeasement, to the invasion of Poland that finally triggered war.

Key forces

The Treaty of Versailles imposed punishing terms on Germany in 1919, generating lasting resentment that fuelled nationalist and extremist politics for two decades.
Economic catastrophe — hyperinflation in the early 1920s and the Great Depression after 1929 — repeatedly destabilised democratic governments and made authoritarian alternatives more attractive.
Fascist movements in Italy and Germany rose to power by exploiting postwar grievances, economic suffering, and the weakness of parliamentary institutions.
The League of Nations failed repeated tests of collective security — in in 1931 and in 1935 — establishing a pattern of impunity for aggressive states.

1919 CE

Step 1 of 101919 CEAccessible mode

The Treaty of Versailles

In June 1919, the victorious Allied powers imposed a peace settlement on Germany at . It was meant to prevent another war. Instead, it planted the seeds of one.

Germany lost significant territory. went to France. A large corridor of land went to the new Polish state, cutting off from the rest of Germany.

A clause assigning full war guilt to Germany provided the legal basis for reparations — enormous payments meant to compensate the Allied powers for the costs of the war.

Germany's military was stripped down. Its army was capped at 100,000 men. Its navy was reduced. No air force was permitted at all.

Most Germans rejected the settlement as a dictated and unjust peace. Resentment ran deep across the political spectrum and never fully faded.

That anger would fuel extreme politics for a generation. Adolf Hitler built his movement on the promise to destroy , and millions listened.

Black-shirted squads and officials move through rain-darkened Rome streets near government buildings during the March on Rome.

1922 CE

Step 2 of 101922 CEAccessible mode

Fascism Takes Power in Italy

In October 1922, Benito Mussolini became prime minister of Italy. It was fascism's first major political victory.

Italy had fought in the First World War on the winning side but came away feeling cheated. The peace settlement had not delivered the territorial gains nationalists expected, and resentment was intense.

Italy's government appeared weak. Strikes paralysed key industries. Socialist movements gained ground. Middle-class voters and landowners wanted order and strong leadership.

Mussolini's Fascist movement offered extreme nationalism, contempt for parliament, and organised violence against political opponents. His Blackshirt squads broke strikes and terrorised left-wing groups.

When fascists marched on in October 1922, the king stepped back and appointed Mussolini as prime minister. Within a few years, Italy had become a one-party dictatorship.

Fascism had proved it could take power. It offered a template for authoritarian movements across Europe, and Hitler in Germany watched Mussolini closely and drew his own lessons.

1923 CE

Step 3 of 101923 CEAccessible mode

The Weakness of the Weimar Republic

Germany's new democracy was born in crisis, and 1923 brought its most dangerous test.

France and Belgium occupied Germany's industrial in January 1923 after Germany fell behind on reparations payments. The German government responded by paying striking workers with newly printed money.

Hyperinflation followed. Prices rose millions of times over in a matter of months. Savings were wiped out overnight. The middle class was ruined, and trust in the new republic collapsed alongside the currency.

Political violence intensified. Communists pushed for revolution. Nationalists blamed the republic for Germany's humiliations. In November 1923, Adolf Hitler led a failed coup in .

The republic survived. A new currency restored stability, and reparations were renegotiated. But the damage to confidence in democracy ran deep and did not fully heal.

The Weimar constitution had built-in weaknesses too. Emergency powers allowed the president to govern by decree. These provisions, later exploited by Hitler, made the constitutional framework fragile from the start.

Premium3 of 10 chapters read

The peace begins to unravel

The settlement after 1919 left tensions unresolved. Next, an economic crisis shakes the world, Japan expands into Manchuria, and the safeguards meant to prevent another war are tested.

Continue the story with Premium

Coming next