Greater Serbia the Kingdom of Serbia retreated from Durrës in April 1913 under pressure of the naval fleet of Great Powers, but it remained in other parts of Albania for the next two months. The secret military society called Unity or Death, popularly known as the Black Hand, headed by Serbian colonel Dragutin Dimitrijević Apis, which took an active and militant stance on the issue of a Greater Serbian state. This organization is believed to have been responsible for numerous atrocities following the Balkan Wars in 1913. In 1914, Young Bosnia member Gavrilo Princip assassinated Archduke Franz Ferdinand in Sarajevo, which set
World War I 1918 influenza pandemic, which caused between 50 and 100 million deaths worldwide. Military losses were exacerbated by new technological and industrial developments and the tactical stalemate caused by gruelling trench warfare. It was one of the deadliest conflicts in history and precipitated major political changes, including the Revolutions of 1917–1923, in many of the nations involved. Unresolved rivalries at the end of the conflict contributed to the start of World War II about twenty years later. On 28 June 1914, Gavrilo Princip, a Bosnian Serb Yugoslav nationalist, assassinated the Austro-Hungarian heir Archduke Franz Ferdinand in Sarajevo, leading to the July