July Crisis

The July Crisis was a diplomatic crisis among the major powers of Europe in the summer of 1914 that led to World War I. Immediately after Gavrilo Princip, a Yugoslav nationalist, assassinated Archduke Franz Ferdinand, heir presumptive to the Austro-Hungarian throne, in Sarajevo, a series of diplomatic maneuverings led to an ultimatum from Austria-Hungary to the Kingdom of Serbia, and eventually to war.

The assassination had been carried out by those wishing to unite all of the territories with majority South Slavic population not already ruled by the Kingdom of Serbia or Kingdom of Montenegro. Austria-Hungary's post-assassination ultimatum was part of a coercive program meant to weaken the Kingdom of Serbia's threat to take control of the northern Balkans and its significant Southern Slavic population, especially the Bosnian Serbs. This was intended to be achieved either through diplomacy or by a localized war if the ultimatum were rejected. Austria-Hungary preferred war, though István Tisza, the prime minister of the Hungarian part of Austria-Hungary, hoped that the ultimatum would be reasonable enough that it would not be rejected outright. A month after the assassination of Franz Ferdinand, Austria-Hungary declared war on Serbia, thus initiating World War I.

Austria-Hungary had annexed Bosnia and Herzegovina in 1908. Sarajevo was the provincial capital. Oskar Potiorek was the military commander and governor of the province. After Potiorek's suggestion, in summer 1913, that Archduke Franz Ferdinand of Austria, heir presumptive to the Austro-Hungarian throne, might attend military exercises due to be held in Bosnia near the end of June 1914,Emperor Franz Joseph ordered Franz Ferdinand to attend. After the exercises, on 28 June 1914, Franz Ferdinand toured Sarajevo with his wife, Sophie, Duchess of Hohenberg. Six armed , five Serbs and one Bosnian Muslim, coordinated by Danilo Ilić, lay in wait along Sarajevo's Appel Quay because it was announced that Franz Ferdinand's motorcade would use that route.

...
Wikipedia