Topic 7.2 Notes – Causes of World War I

Why World War I Broke Out in 1914

You want to separate three layers of cause. The long-term causes made Europe unstable. The assassination explains why then. The July Crisis explains how leaders turned danger into war.

By 1900, Europe had the tools for a huge war:

• Industrialized states could mass-produce rifles, artillery, and shells.
• Mass conscription let governments call up millions of soldiers.
• Railroads moved troops fast, which made mobilization feel urgent.
• Modern weapons and war plans made leaders think in rigid timetables.

Multiethnic empires were especially shaky:

• Austria-Hungary ruled many ethnic groups, including Slavs who wanted more autonomy.
• The Ottoman Empire was weakening, which opened power struggles in southeastern Europe.

The AP move is never “WWI had one cause.” It came from the interaction of imperialism, nationalism, alliances, territorial disputes, and militarism.

The Main Long-Term Causes

Imperialism and competition for power and resources

Empires meant raw materials, markets, military bases, and prestige. Colonies were money and status at the same time.

• Germany’s Weltpolitik under Kaiser Wilhelm II pushed for a stronger navy and bigger global role, which alarmed Britain and France.
• The First Moroccan Crisis (1905 to 1906) and Second Moroccan Crisis (1911 at Agadir) grew out of Germany challenging French influence in Morocco. These crises ended peacefully, but they increased distrust and pushed Britain and France closer together.
• Imperial rivalry also helps explain why the war became global, since empires pulled in colonies, soldiers, and overseas territory.

Territorial and regional conflicts

Some tensions were inside Europe itself. The map here is most useful for spotting the rival alliance blocs and why the Balkans mattered so much.

Europe and the alliance system, 1914

• Alsace-Lorraine had been taken by Germany from France after the Franco-Prussian War, so France carried resentment into 1914.
• The Balkans were the “powder keg of Europe” because Ottoman decline left a power vacuum.
• Austria-Hungary feared a stronger Serbia.
• Russia wanted influence in the Balkans and access through the Turkish Straits.
• In the Bosnian Crisis of 1908, Austria-Hungary annexed Bosnia and Herzegovina, angering Serbia and Russia.
• The Balkan Wars of 1912 to 1913 made Serbia stronger, which made Austria even more nervous.

Nationalism

Nationalism worked in two ways:

• State nationalism tied national greatness to military power, empire, and honor.
• Ethnic nationalism pushed groups inside empires to seek independence.

That second kind mattered a lot in the Balkans:

• Serbian nationalism and Yugoslavism aimed to unite South Slavs.
• Pan-Slavism connected Serbia to Russian support.

Nationalism made compromise look weak. A local dispute could feel like a test of national survival.

Alliances and militarism

Europe split into rival camps:

These alliances were not fully automatic, which is a common AP trap. Leaders still made choices. Still, they made every crisis more dangerous.

• Militarism meant glorifying military strength and accepting force as a solution.
• Britain and Germany competed in a naval arms race, especially after HMS Dreadnought in 1906.
• The Schlieffen Plan, mobilization schedules, and conscription made slow diplomacy harder.

The acronym MAIN helps, but you still need territorial conflict and the July Crisis to explain the war.

How the Balkans Turned Tension into Crisis

Serbia backed South Slav nationalism, which directly threatened Austria-Hungary’s unity. Russia backed Serbia for Pan-Slavic reasons and for strategic influence.

On June 28, 1914, Archduke Franz Ferdinand was assassinated in Sarajevo by Gavrilo Princip, a Bosnian Serb nationalist tied to Young Bosnia. The Black Hand helped arm the conspirators.

Archduke Franz Ferdinand in Sarajevo, 1914

This photo shows Franz Ferdinand in Sarajevo shortly before the assassination. The killing mattered because it confirmed Austrian fears and gave Austria-Hungary a reason to crush Serbia.

How the July Crisis Became a European War

Here’s the chain reaction:

1. July 5 to 6. Germany gave Austria-Hungary a blank check and promised support.
2. July 23. Austria-Hungary sent Serbia a harsh ultimatum.
3. Serbia accepted most demands but rejected ones that violated its sovereignty.
4. July 28. Austria-Hungary declared war on Serbia.
5. Russia mobilized to support Serbia.
6. August 1. Germany declared war on Russia.
7. August 3. Germany declared war on France.
8. Germany invaded neutral Belgium under the Schlieffen Plan.
9. August 4. Britain declared war on Germany.

The key point is that alliances did not force war like dominoes. Leaders made choices inside a system already loaded with pressure.

Why the War Became Global

European empires spread the war far beyond Europe.

• Britain, France, Germany, and Russia drew on colonies and dominions for troops, labor, food, and raw materials.
• Japan entered in 1914 and seized German possessions in East Asia and the Pacific.
• The Ottoman Empire joined the Central Powers, expanding the war into the Middle East.

So the clean causal summary is this:

• Long-term causes were imperialism, nationalism, territorial rivalry, alliances, and militarism.
• Immediate trigger was Sarajevo.
• Escalation mechanisms were the blank check, ultimatum, mobilization, and Schlieffen Plan.
• Result was a Balkan crisis that became a European war and then a global war.