1. Ultimatum to Serbia: Following the assassination of Archduke Franz Ferdinand in Sarajevo on June 28, 1914, Austria-Hungary issued an ultimatum to Serbia that historians widely consider to be deliberately provocative and unacceptable. It included demands that infringed upon Serbia's sovereignty and aimed to weaken its influence in the Balkans. Serbia reluctantly accepted most of the demands but could not agree to all of them without compromising its status as an independent state.
2. Backing from Germany: Austria-Hungary had strong support from Germany, led by Emperor Wilhelm II and Chancellor Theobald von Bethmann Hollweg. German officials pledged unconditional support to Austria-Hungary even if its actions resulted in war. This "blank check" emboldened Austria-Hungary to take a more aggressive stance against Serbia, knowing that it had Germany's full backing.
3. Desire to Maintain the Status Quo: Austria-Hungary, as a multinational empire, faced growing nationalist movements and internal tensions. By taking a firm stance against Serbia and its support for Slavic nationalism in the Balkans, Austria-Hungary hoped to suppress these internal challenges and preserve its territorial integrity.
4. Failure of Diplomacy: Despite attempts by other European powers to mediate, diplomatic efforts failed to resolve the crisis between Austria-Hungary and Serbia. Each side maintained its positions, leading to increased tension and animosity in the region. Miscommunication, misunderstandings, and a lack of effective communication channels also contributed to the escalation of the conflict.
It's important to note that while Austria-Hungary played a leading role in triggering the chain of events that led to war, multiple factors on a broader scale, including geopolitical rivalries, nationalism, militarism, and a complex web of alliances, contributed to the outbreak of World War I. To accurately understand the war's origins, historians take a broader perspective examining the interconnections between various international developments and diplomatic failures leading up to 1914.