What were the main causes of the First World War?
Short answer
Historians often group the long-term causes as militarism, alliances, imperialism and nationalism. The short-term trigger was the assassination of Archduke Franz Ferdinand of Austria-Hungary in Sarajevo on 28 June 1914. Because of the alliance system, a regional crisis between Austria-Hungary and Serbia became a European war within weeks.
Step by step
- Militarism: an arms race, including the naval race between Britain and Germany, and detailed war plans such as the Schlieffen Plan.
- Alliances: the Triple Entente (Britain, France, Russia) faced the Triple Alliance (Germany, Austria-Hungary, Italy).
- Imperialism: rivalry for colonies, including two crises over Morocco.
- Nationalism: Slav nationalism in the Balkans threatened Austria-Hungary.
- The trigger: after the assassination, Austria-Hungary declared war on Serbia; Russia mobilised, Germany declared war on Russia and France, and invaded Belgium, bringing Britain in.
Worked example
How to reach a judgement
- Do not just list the causes; explain how they connect
- For example, the alliances turned a local conflict into a wider war, but militarism made governments willing to act quickly
- Finish by stating which cause you think mattered most, and why
Common mistakes
- Treating the assassination as the only cause.
- Listing causes without linking them to the outbreak of war.
- Getting the alliances wrong: Italy did not fight with Germany and in 1915 joined the Allies.
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