Conversation so far:
Are there any other interesting aspects about the Franz Joseph I of Autria article?
the assassination of Franz Joseph's  nephew and heir-presumptive, Archduke Franz Ferdinand, in Sarajevo resulted in Austria-Hungary's declaration of war against the Kingdom of Serbia
When did  occur the assassination of his nephew and heir-presumptive, Archduke Franz Ferdinand, in Sarajevo that  resulted in Austria-Hungary's declaration of war against the Kingdom of Serbia?
On June 28, 1914

Question: How did this contribute to the out break of the war?
Self-contained rewrite: How did the assassination of his nephew and heir-presumptive, Archduke Franz Ferdinand, in Sarajevo that resulted in Austria-Hungary's declaration of war against the Kingdom of Serbia that contributed to the out break of the war On June 28, 1914?