Sign Up
School Account Sign Up
Contributor: Elephango Editors. Lesson ID: 11015
How did one assassination trigger a global war? Explore the causes of WWI and see how militarism, alliances, nationalism, and imperialism set the stage for one of history’s deadliest conflicts.
A Chain Reaction of Chaos
Imagine this: A single event creates a domino effect that drags entire countries into chaos. One moment, Europe is at peace. The next, millions of soldiers are marching into battle.
World War I didn’t start with one cause—it started with five. These five causes were like dry wood waiting for a spark.
The assassination of a single man.
By the end of this lesson, you’ll see how a war that started over a century ago still echoes in conflicts today. Pay close attention—some of the reasons behind WWI might remind you of headlines you’ve seen in the news.
Why Did World War I Happen?
World War I, also known as the Great War, lasted from 1914 to 1918. But its causes had been building for years.
Historians point to five main reasons the war erupted, and together, they spell out the word MANIA.
Each played a crucial role in turning a conflict between two countries into a war that engulfed the world.
Militarism: The Armed Race
Imagine living in a country where your government constantly builds bigger, stronger armies.
In the early 1900s, European nations were obsessed with growing their military power. Germany, Britain, France, and Russia all expanded their armies and developed new weapons.
This arms race made war seem almost inevitable—each country wanted to prove it was the strongest.
Alliances: Friends and Foes
When you disagree with a friend, it usually stays between you two.
That’s what happened before WWI. European countries had formed military alliances, promising to defend each other if attacked. There were two major alliances.
Triple Entente: France, Russia, and Great Britain
Triple Alliance: Germany, Austria-Hungary, and Italy (Italy later switched sides.)
This meant that if war started between two countries, their allies would be forced to join, turning a minor conflict into a world war.
Nationalism: My Country, My Pride
In many European countries, nationalism was growing stronger. Nationalism is the belief that your country is better than all others. It can create unity, but it can also lead to dangerous rivalries.
In the Balkans, different ethnic groups wanted independence from powerful empires like Austria-Hungary. Meanwhile, Germany wanted to prove its dominance over Britain and France.
This intense national pride led to tensions boiling over.
Imperialism: A Fight for Land
By the early 1900s, European countries had been competing for colonies worldwide. Britain and France controlled large empires, while Germany wanted more land to expand its power.
These rivalries increased tension—each country feared the others were trying to conquer more territory. When war broke out, it quickly spread beyond Europe to Africa and Asia.
Assassination: The Final Spark
On June 28, 1914, a Serbian nationalist named Gavrilo Princip assassinated Archduke Franz Ferdinand, the heir to the Austro-Hungarian throne.
Austria-Hungary blamed Serbia for the attack and declared war. Because of the web of alliances, other nations jumped in, and within weeks, World War I had begun.
At first, some leaders thought the war would be quick. Instead, it became one of the deadliest conflicts in history.
You now know the five key causes of World War I—militarism, alliances, nationalism, imperialism, and assassination.
Head to the Got It? section to find out!
Supplies
FAVORITE
Like