Mladen Stojanović members of the association, whom he sometimes sharply criticised. Nevertheless, younger students liked being around him. Gaković described him as a tall and handsome man who greatly cared about his appearance; he wore a bow tie and a broad-brimmed hat. On the morning of 28 June 1914, in Sarajevo, Princip assassinated Archduke Franz Ferdinand of Austriaheir presumptive to the throne of Austria-Hungaryand his wife Sophie. Princip was a member of a group of conspirators, which included Trifko Grabež; the whole group was arrested by the Austrian police after the assassination. Blaming Serbia for the attack, Austria-Hungary declared war a month
Serbs internationally until the Congress of Berlin in 1878. Serbia fought in the Balkan Wars of 1912–13, which forced the Ottomans out of the Balkans and doubled the territory and population of the Kingdom of Serbia. In 1914, a young Bosnian Serb student named Gavrilo Princip assassinated Archduke Franz Ferdinand of Austria, which directly contributed to the outbreak of World War I. In the fighting that ensued, Serbia was invaded by Austria-Hungary. Despite being outnumbered, the Serbs subsequently defeated the Austro-Hungarians at the Battle of Cer, which marked the first Allied victory over the Central Powers in the war. Further victories