. The First World War began in the summer of 1914, shortly after the assassination of Austria’s Archduke, Franz Ferdinand, and lasted more than four years, ending in 1918. Though the assassination of Archduke Ferdinand was the direct precipitating event leading to the declaration of war, there were many other factors that also played a role in leading up to World War I.
In the 1900s, several European nations had empires across the globe, where they had control over vast swaths of lands. colonizing regions like India, modern-day Vietnam and West and North Africa. The expansion of European nations as empires can be seen as a key cause of World War I, because as European powers expanded their empires, it resulted in increased tensions among European countries.
Nationalism was one of many political forces at play in the time leading up to World War I, with Serbian nationalism in particular, playing a key role. Serbian nationalism can be dated to the mid- and late-1800s, though two precipitating nationalism events are directly linked to the start of WWI. In the Balkans, Slavic Serbs sought independence from Austria-Hungary and the Ottoman Empire, and in 1878, they tried to gain control of Bosnia and Herzegovina to form a unified Serbian state. With the decline of the Ottoman Empire, Serbian nationalism continued to rise, culminating in the assassination of the Archduke of Austria in 1914 by a Bosnian Serb and officially triggering the start of the Great War.
In the age of imperialism prior to World War I, countries throughout Europe had created alliances. The alliances promised that each country would support the other if war ever broke out between an ally and another Great Power. Prior to WWI, the alliances of Russia and Serbia; France and Russia; Germany, Italy and Austria-Hungary; Britain, France and Belgium; France, Britain and Russia; and Japan and Britain were firmly in place. The alliance, between France, Britain and Russia, formed in 1907 and called the Triple Entente, caused the most friction among nations. Germany felt that this alliance surrounding them was a threat to their power and existence. As tensions continued to rise over alliances, the preexisting alliances fed into other countries declaring war against one another in the face of conflict.