1.Alliance System and International Rivalry:
- Triple Alliance: Germany, Austria-Hungary, and Italy formed the Triple Alliance in 1882, focused on maintaining the status quo in Europe and preventing the rise of rival powers.
- Triple Entente: In 1907, Britain, France, and Russia formed the Triple Entente in response to Germany's growing power and an agreement, to support each other in case of war.
- Entangling Alliances: As these alliances developed, a system of mutual obligations emerged, turning a localized conflict into a continent-wide war.
2. Imperial Expansion and Colonial Rivalries:
- Territorial Disputes: European powers competed for colonies and territories in Africa, the Middle East, and Asia, with rivalries intensifying over control of resources and strategic regions.
- Expansionist Ambitions: Germany's desire for a global empire clashed with the established interests of Britain and France, particularly in Africa.
3. Nationalism and Irredentism:
- Rising National Sentiment: Rising nationalist movements in the Balkans and parts of Europe sought self-determination and territorial expansion, leading to increased tensions between ethnic groups and empires.
- Irredentism: The desire to reclaim territories inhabited by ethnic groups outside national borders fueled conflicts between Austria-Hungary and Serbia, contributing to the start of the war.
4. Militarism and Arms Race:
- Buildup of Military Power: European powers engaged in a rapid arms race, increasing military spending and building up their armed forces.
- Arms Competition: The build-up of military power created an atmosphere of fear and suspicion among nations and reduced the threshold for war.
5. Assassination of Archduke Franz Ferdinand:
- Trigger Event: The assassination of Archduke Franz Ferdinand, heir to the Austro-Hungarian throne, on June 28, 1914, served as the immediate trigger for the outbreak of war.
- Diplomatic Crisis: Diplomacy failed to resolve the ensuing diplomatic crisis, as Germany supported Austria-Hungary's aggressive stance against Serbia.
6. Outbreak of War and Global Expansion:
- Declaration of War: Austria-Hungary declared war on Serbia on July 28, 1914, marking the beginning of World War I.
- Chain Reaction: The complex system of alliances led to a chain reaction, as Russia mobilized in support of Serbia, Germany declared war on Russia and France, and Britain joined the war on the side of France and Belgium.
- Global Spread: As the war progressed, it spread beyond European borders due to the involvement of various colonies, territories, and international allies, transforming it into a global conflict.
7. Colonial Campaigns and Overseas Theaters:
- Colonial Engagements: European powers involved their colonies and overseas territories in the war, expanding the conflict to Africa, the Middle East, the Pacific, and other regions.
8. Technological Advancements and Warfare Expansion:
- Use of Advanced Technology: The war witnessed the widespread use of new military technologies, such as long-range artillery, submarines, tanks, and aircraft, which extended the reach and impact of combat.
Collectively, these factors explain the transformation of World War I from a regional European conflict to a global war that involved dozens of countries and impacted millions of people worldwide.