Battle of Kolubara their respective commands, and the 5th and 6th armies were merged into a single 5th Army of 95,000 men. On 28 June 1914, Bosnian Serb student Gavrilo Princip assassinated Archduke Franz Ferdinand of Austria in Sarajevo. The assassination precipitated the July Crisis, which led Austria-Hungary to issue an ultimatum to Serbia on 23 July on suspicion that the assassination had been planned in Belgrade. The Austro-Hungarian government made the ultimatum intentionally unacceptable to Serbia, and it was indeed rejected. The Austro-Hungarians declared war on Serbia on 28 July and that same day the Serbs destroyed all bridges on the Sava
Assassination of Archduke Franz Ferdinand The five bullets Žerajić fired at Varešanin and the fatal bullet he put in his own brain made Žerajić an inspiration to future assassins, including Princip and Princip's accomplice Čabrinović. Princip said that Žerajić "was my first model. When I was seventeen I passed whole nights at his grave, reflecting on our wretched condition and thinking of him. It is there that I made up my mind sooner or later to perpetrate an outrage." In 1913, Emperor Franz Joseph commanded Archduke Franz Ferdinand to observe the military maneuvers in Bosnia scheduled for June 1914. Following the maneuvers, Ferdinand and his