1. Immediate Spark: The assassination ignited tensions between Austria-Hungary and Serbia. Austria-Hungary, supported by Germany, saw the assassination as a Serbian conspiracy to destabilize the region. They issued an ultimatum to Serbia with harsh demands, including the arrest and punishment of those involved in the plot.
2. Austro-Hungarian Ultimatum: Serbia partially accepted the ultimatum but rejected some terms. Austria-Hungary, viewing this as defiance, declared war on Serbia on July 28, 1914, after diplomatic efforts failed to resolve the crisis.
3. Russian Mobilization: Russia, a Slavic ally of Serbia, began to mobilize its military in support of Serbia. Germany, fearing a two-front war against France and Russia, issued an ultimatum to Russia to halt mobilization. Russia's refusal prompted Germany to declare war on Russia on August 1, 1914.
4. German Invasion of Belgium: To quickly defeat France, Germany invaded Belgium, violating the country's neutrality. Britain, which had guaranteed Belgian neutrality, declared war on Germany on August 4, 1914.
5. System of Alliances: The complex system of alliances among European powers created a domino effect. France and Russia were allies of Serbia, while Germany and Austria-Hungary were allies of each other. The actions of one country triggered the obligations of its allies, leading to a chain reaction of military mobilizations and declarations of war.
6. Balkan Powder Keg: The Balkans region had long been a source of tension and conflict in Europe. The assassination and its aftermath brought these tensions to a head, sparking a wider European conflict.
In conclusion, the assassination of Archduke Franz Ferdinand was the catalyst that set off a series of events and diplomatic tensions that culminated in the outbreak of World War I. While the assassination alone may not have been sufficient to cause the war, it was the immediate trigger that ignited the preexisting rivalries and alliances among European powers, ultimately leading to the global conflict.