Causes of World War 1
World War 1 broke out in 1914 and lasted until 1918. It was the deadliest conflict the world had ever seen, killing around 20 million people. But it did not start overnight. Tensions had been building across Europe for decades, and when the spark finally came, the entire continent was dragged into war. To understand how, you need to know MAIN.
MAIN: The Four Long-Term Causes
Key Fact Box: MAIN
- M - Militarism: European powers were in an arms race. Between 1870 and 1914, military spending across Europe more than doubled. Germany and Britain competed fiercely to build the largest navy. Countries glorified military power and believed war was a legitimate way to solve disputes. By 1914, every major European power had vast armies ready to mobilise at short notice.
- A - Alliances: Europe was divided into two major alliance systems. The Triple Alliance (Germany, Austria-Hungary and Italy) and the Triple Entente (France, Russia and Britain). These alliances meant that a conflict between two countries could drag in all the others. They were designed as deterrents but ended up being escalators.
- I - Imperialism: European powers competed to control territories in Africa, Asia and beyond. Britain and France had enormous empires, and Germany wanted its "place in the sun." Colonial rivalries created jealousy, suspicion and several near-conflicts in the years before 1914, including the Moroccan Crises of 1905 and 1911.
- N - Nationalism: Fierce national pride was surging across Europe. Countries believed their nation was superior and had the right to dominate others. In the Balkans, Slavic nationalists wanted independence from Austria-Hungary, which created a powder keg of ethnic tensions in south-eastern Europe.
The Assassination of Archduke Franz Ferdinand
On 28 June 1914, Archduke Franz Ferdinand of Austria-Hungary was visiting Sarajevo, the capital of Bosnia. Bosnia had been annexed by Austria-Hungary in 1908, which angered Serbian nationalists who believed Bosnia should be part of a greater Serbia.
A group of young nationalists called the Black Hand planned to assassinate the Archduke. The first attempt, a bomb thrown at his car, failed. But later that day, the Archduke's driver took a wrong turn and stopped the car right in front of one of the conspirators, Gavrilo Princip. Princip fired two shots, killing both the Archduke and his wife Sophie.
This assassination was the spark that lit the fuse. It did not cause the war by itself, but it triggered a chain reaction that the alliance system turned into a continental conflict.
The Alliance Chain Reaction
After the assassination, Austria-Hungary blamed Serbia and issued an ultimatum with deliberately impossible demands. When Serbia did not fully comply, Austria-Hungary declared war on Serbia on 28 July 1914. Then the alliances kicked in:
- Russia mobilised to support Serbia (Slavic solidarity).
- Germany declared war on Russia to support Austria-Hungary.
- Germany then declared war on France (Russia's ally) and invaded Belgium to reach France quickly via the Schlieffen Plan.
- Britain declared war on Germany because Britain had guaranteed Belgian neutrality in the Treaty of London 1839.
Within six weeks, a political assassination in the Balkans had turned into a war involving every major European power.
Timeline of Key Events
- 28 June 1914: Archduke Franz Ferdinand assassinated in Sarajevo.
- 23 July 1914: Austria-Hungary issues ultimatum to Serbia.
- 28 July 1914: Austria-Hungary declares war on Serbia.
- 1 August 1914: Germany declares war on Russia.
- 3 August 1914: Germany declares war on France; invades Belgium.
- 4 August 1914: Britain declares war on Germany.
- August 1914: The Ottoman Empire and Japan enter the war in the following weeks, making it truly global.
Worked Example: Exam Approach
If asked "What were the causes of World War 1?", do not just list MAIN. The best answers explain how the long-term causes (MAIN) created the conditions for war, and how the short-term trigger (the assassination) set off the alliance system. Show links between the causes: for example, nationalism in the Balkans led to the assassination, which activated the alliances, which had been strengthened by militarism and imperial rivalry.
Practice Questions
- Explain how militarism contributed to the outbreak of World War 1.
- Why did the assassination of Archduke Franz Ferdinand lead to a wider European war? Refer to the alliance system in your answer.
- Which long-term cause do you think was most important in causing WW1? Justify your answer.
- Create a diagram showing how the alliance system turned a regional conflict into a world war.