Several historical factors contributed to the onset of World War I, including militarism, alliances, imperialism, and nationalism. The buildup of military forces and aggressive foreign policies among European powers fostered an atmosphere of tension. Complex alliances, such as those between the Triple Alliance and Triple Entente, created a situation where a regional conflict could escalate into a larger war. Nationalistic fervor, particularly in the Balkans, fueled desires for independence and territorial expansion. The assassination of Archduke Franz Ferdinand of Austria in 1914 acted as a catalyst, triggering a series of events that ultimately led to the outbreak of the devastating global conflict.