1. Pan-Slavism: Serbia promoted the idea of Pan-Slavism, advocating for the unification of all Slavic peoples. Many Serbs saw Slavic populations living within Austria-Hungary, particularly in Bosnia and Herzegovina, as oppressed, and aimed to liberate them and incorporate these regions into a Greater Serbia.
2. Austro-Hungarian Concerns: Austria-Hungary viewed Serbia's nationalist ambitions as a threat to the stability and integrity of its multi-ethnic empire. The Hapsburg monarchy feared the potential loss of Slavic territories to Serbia, which could encourage Slavic separatism within the empire.
3. Balkan Rivalries: Serbian ambitions clashed with those of other Balkan countries, such as the Ottoman Empire, Bulgaria, and Montenegro, all vying for control and influence in the region. This rivalry further complicated political dynamics and created a volatile atmosphere in the Balkans.
4. Annexation of Bosnia and Herzegovina: In 1908, Austria-Hungary annexed Bosnia and Herzegovina, regions inhabited by a substantial Slavic population. Serbia perceived this annexation as an act of aggression against its national interests, leading to outrage and protests.
5. Arms Race and Alliances: The heightened tensions between Serbia and Austria-Hungary fueled an arms race between the two countries. Serbia formed close relations with Russia, while Austria-Hungary aligned itself with Germany. The alliances further solidified the division of Europe into opposing blocs and increased the risk of a full-scale conflict.
6. Assassination of Archduke Franz Ferdinand: The pivotal event that ignited World War I was the assassination of Archduke Franz Ferdinand, heir to the Austro-Hungarian throne, by a Serbian nationalist named Gavrilo Princip on June 28, 1914. This event triggered a series of diplomatic crises and ultimately led to the outbreak of war.
Therefore, Serbia's sense of nationalism, combined with its desire to unify South Slavic peoples, the annexation of Bosnia and Herzegovina by Austria-Hungary, and the subsequent alliances and arms race, all contributed to the tensions and hostilities in Europe that culminated in the start of World War I.