World War I was caused by increasing tensions between European powers due to militarism, alliances, imperialism, and nationalism in the late 19th and early 20th centuries. Militarism led to an arms race and glorification of military strength, imperialism increased competition over colonies, and alliances divided Europe into opposing factions. Nationalism further heightened tensions, especially in the Balkans where Slavic nationalism challenged Austrian rule. The assassination of Archduke Franz Ferdinand by a Serbian nationalist triggered a series of events that caused the powers to take sides and engage in World War I.

1.  Essential Question:
 What caused World War I?

2.  Text
From 1914 to 1919, World War I erupted in Europe
This “Great War” was the largest,
most destructive war the world had
yet seen
WWI was a global war that
altered the course of the 20th
century
What caused World War I?

3. From 1870 to 1914, a number of developments gradually
increased tensions among the European powers that led to the
outbreak of World War I
The
MILITARISM
ALLIANCES
IMPERIALISM
NATIONALISM
causes of World War I

4. MILITARISM
The Industrial Revolution
led to large, advanced
militaries in Europe
Europeans believed that
to be great, nations had
to have strong militaries
As a result, an arms race began among European
nations, especially between Britain & Germany
Nations glorified
military power &
kept an army
prepared for war
(called militarism)
Having a strong
army increased
patriotism among
citizens

5. IMPERIALISM
European nations competed fiercely
for colonies in Africa & Asia
Competition for colonies
often pushed Europeans
to the brink of war
This competition increased
European rivalry & mistrust
Germany &
France almost
went to war
three times
over Morocco
Germany, Englan
d, Russia argued
over building a
railroad in India
England
& France
argued over
rights to the
Sudan

6. ALLIANCES
Growing rivalries among nations led to the
formation of two military alliances that
threatened to draw European nations into war
Germany, Italy, &
Austria-Hungary made
up the Triple Alliance
England, France,
& Russia formed
the Triple Entente

7. NATIONALISM
Austrian national poster, 1900
Rivalries due to
militarism & imperialism
increased nationalism
among European powers
British propaganda poster, 1897
European rivals tried to
maintain a balance of
power while also trying
to overpower each other
“European Balance of Power, 1914”

8. NATIONALISM
While nationalism unified
people in the powerful
nations, it was dividing
people in weakening empires
No region was more
tense in the years
before World War I
than the Balkans
Serbia, Greece, Albania,
Bulgaria, & Romania
broke from the
Ottoman Empire to
create new nations
Slavic people in Serbia
wanted to unify all Slavs
but Austria-Hungary
opposed giving up the
largely Slavic territories
Bosnia & Herzegovina
The Balkans became a
“powder keg” waiting
for a spark to blow up

9. The Outbreak of World War I
Serbians vowed
to take Bosnia &
Herzegovina from
Austria-Hungary
On June 28, 1914, the Austro-
Hungarian Archduke Franz
Ferdinand & his wife were
assassinatedbyaSerbianterrorist
The assassin Gavrilo Princip

10. The Outbreak of World War I
On July 23, Austria-Hungary
issued an ultimatum to Serbia:
turn over conspirators & allow
an investigation…OR…go to war
When Serbia balked at some
of the terms, Austria-Hungary
declared war on June 28, 1914
Russia had a large
population of Slavs &
was an ally of Serbia;
Russia moved troops
to the Austrian border
These events set off
a chain reaction that
started World War I

11. World War 1 BeginsAustria-Hungary
declared war on Serbia
& its ally Russia
On July 28,1914, Serbia
declined the ultimatum
On August
1, 1914, Germany
declared war on Russia
On August
3, 1914, Germany
declared war on
France
Italy backed out of its
agreement with Germany
& Austria-Hungary…
…and joined
the Allies
On August 4, 1914, England
declared war on Germany &
Austria-Hungary
Russia mobilized for war
to protect Serbia
World War I had begun

12. During the war Germany & Austria-Hungary
became the Central Powers; They were
joined by Bulgaria & the Ottoman Empire
The members of the Triple Entente
became known as the Allied Powers
and eventually were joined by…

13. …many nations throughout the world