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
Serbia to become an anchor for unification of all South Slavs, and the relationship between the two countries became tense. The assassination of Archduke Franz Ferdinand of Austria on 28 June 1914 in Sarajevo by Gavrilo Princip, a member of the Young Bosnia organization, led to Austria-Hungary declaring war on Serbia. In defense of Serbia, and to maintain her status as a Great Power, Russia mobilized its troops, which resulted in Austria-Hungary's ally Germany declaring war on Russia. Serbia won the first major battles of World War I, including the Battle of Cer and Battle of Kolubara – marking the first