Veljko Čubrilović Veljko Čubrilović Veljko Čubrilović (Serbian Cyrillic: Вељко Чубриловић; 6 June 1886 – 3 February 1915) was a Bosnian Serb who was involved in the assassination of Archduke Franz Ferdinand of Austria. He was born in Gradiška, Bosnia and Herzegovina and became a schoolteacher in Priboj Majevički. In 1914, as a member of the Black Hand secret society, he agreed to help Gavrilo Princip, Nedeljko Čabrinović, and Trifko Grabež assassinate Archduke Franz Ferdinand. His brother, Vaso Čubrilović, was also involved in the plot. On Sunday, 28 June 1914, Franz Ferdinand and Sophie von Chotkova were assassinated by Gavrilo Princip. Princip and
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