The immediate cause of World War I was the assassination of Archduke Franz Ferdinand of Austria, which took place on June 28, 1914, in Sarajevo, the provincial capital of Bosnia-Herzegovina (formally annexed by Austria-Hungary in 1908).
Nationalism and Imperialism:
- Growing nationalist sentiments and rivalries among European powers
- Imperial expansion and competition for colonies
- Militarism and Arms Race:
- Build- up of powerful military forces and stockpiling of weapons
Balkan Powder Keg:
- Complex web of alliances and rivalries in the Balkans
- Desire of Balkan states to gain independence from the Ottoman Empire
Failure of Diplomacy:
- Diplomatic efforts failed to resolve tensions between Austria-Hungary and Serbia
- Ultimatum issued by Austria-Hungary to Serbia, which was seen as too harsh
Russian Support for Serbia:
- Serbia's reliance on Russia for protection
- Russia's interest in maintaining influence in the Balkans
- Mobilization of Russian forces in response to Austria-Hungary's actions
Chain Reaction of Alliances:
- Activation of alliance system due to interlocking treaties
- Germany backed Austria-Hungary, France supported Russia and Britain supported Belgium
Schlieffen Plan:
- German military strategy to defeat France quickly before turning eastward to face Russia
- Required violating Belgian neutrality, which brought Britian into the war