World War I: Causes, Course, and the Treaty of Versailles

One shot in Sarajevo, and Europe slid into four years of war. Then a peace treaty tried to settle the score. It left many problems open.

This lesson follows the war in order. First the causes, then the fighting, then the peace of 1919.

1How did one assassination start a world war?

On 28 June 1914 a Bosnian Serb nationalist shot Archduke Franz Ferdinand in Sarajevo. He was heir to the Austro-Hungarian throne.

The next five weeks are called the July Crisis. Austria-Hungary declared war on Serbia on 28 July. Alliances then pulled the other great powers in.

Europe split into two camps. The Allied Powers faced the Central Powers. Germany expected a quick win over France before turning east against Russia.

That plan failed at the First Battle of the Marne in September 1914. The fast war never came.

• Trigger: the Sarajevo assassination, 28 June 1914.
• Austria-Hungary declared war on Serbia on 28 July.
• Germany’s quick-win plan failed at the Marne.

2Why did the fighting turn into a stalemate?

After the Marne, both sides dug trenches across the Western Front. Armies then sat facing each other for years.

New weapons made attacking deadly. Poison gas, tanks and aircraft all appeared. Battles like Verdun and the Somme cost huge numbers of lives.

Often the front line moved only a little. That is why the war felt endless.

Why does this matter? Industrial weapons made defence stronger than attack. Armies could not break through.

• Trenches ran across the Western Front.
• New weapons: gas, tanks, aircraft.
• Verdun and the Somme: vast losses, small gains.

3Why did America enter the war in 1917?

At first the United States stayed neutral. Two things changed that.

Germany resumed unrestricted submarine warfare. Its U-boats now attacked ships without warning, including neutral ones.

Britain also intercepted the Zimmermann Telegram. In it, Germany suggested an alliance with Mexico against the United States.

Congress declared war on 6 April 1917. Fresh American strength helped tip the balance toward the Allies.

• Cause one: unrestricted submarine warfare.
• Cause two: the Zimmermann Telegram.
• War declared on 6 April 1917.

4What did the Treaty of Versailles demand of Germany?

The fighting stopped with the armistice on 11 November 1918. The peace treaty came later. It was signed on 28 June 1919, exactly five years after Sarajevo.

Germany was not allowed to join the talks before signing. The treaty took away land, including Alsace-Lorraine, which went back to France.

It also limited the German army to 100,000 men. Article 231 made Germany accept responsibility for the war. People call it the “War Guilt” clause.

Money was part of the deal too. In 1921 the Allies fixed the reparations bill at 132 billion gold marks. Germany finally paid off its Versailles debts in 2010, after the sum had been cut in half in 1953.

• Signed 28 June 1919.
• Article 231: the “War Guilt” clause.
• Army capped at 100,000 men.
• Reparations set in 1921 at 132 billion gold marks.

5Which empires fell because of the war?

Four great empires collapsed. They were the Russian, Austro-Hungarian, Ottoman and German empires.

Their fall redrew the map. New states appeared in Europe and the Middle East. The Russian Revolution had already ended the tsar’s rule in 1917.

Why does this matter? Many modern borders trace back to these years.

• Fallen: Russian, Austro-Hungarian, Ottoman, German.
• Result: new states and new borders.

6Why was the League of Nations weak from the start?

The League of Nations was created after the war. Its goal was to prevent another one.

The idea came largely from US President Woodrow Wilson. Yet the United States never ratified the Versailles Treaty. It made a separate peace with Germany.

Without America, the League lacked a major power from day one.

• Idea from Woodrow Wilson.
• The US never joined.
• Goal: stop future wars through cooperation.

7Did Versailles lead to Hitler?

Many historians argue the treaty fed German anger. Economic crisis added to it later. Hitler used both.

Others say the treaty alone was not the cause. The Great Depression and weak politics also mattered. Keynes called the treaty a “Carthaginian peace”, a harsh one.

Why does this matter? A strong answer shows both views. It avoids saying Versailles alone caused the next war.

• View one: harsh terms fed resentment.
• View two: the Great Depression also mattered.
• Critic: Keynes thought reparations were excessive.

8What are the exam traps?

• UPSC Mains 2024 asked about World War I and the balance of power. Name the alliance system and how it turned a crisis into war (Source: UPSC Mains 2024 GS1 Q12).
• America entered because of both U-boats and the Zimmermann Telegram, not one alone.
• The 132 billion figure came in 1921, not at Versailles itself.
• Germany did not finish paying within a decade.