Called to revise the Treaty of San Stefano; recognized independence of Romania, Serbia, and Montenegro as well as Bulgaria.
Austria - Hungary enters an alliance with Serbia in order to prevent Russia from gaining too much influence in the Balkans and to prevent Russian aggression in Serbia.
Germany, Austria–Hungary, and Italy enter an alliance enter an alliance that lasts until the beginning of World War I. Italy goes against the alliance shortly after the beginning of WWI.
Serbian King Alexander Obrenović and his wife, Queen Draga, were assassinated inside the Royal Palace in Belgrade. Led to the extinction of the House of Obrenović, replaced by the House of Karađorđević. The House of Karađorđević was associated with Russia and France while the House of Obrenović was associated with Austria - Hungary. The May Overthrow strained relations between Austria - Hungary and Serbia, and led to the Customs War when Serbia tried to become less dependent on Austria - Hungary.
Also known as the Pig War - Austria-Hungary imposes a customs blockade on Serbian pork. Austria - Hungary attempted to stop Serbian growth; in response, Serbia found new partners to export pork to and increased its trade.
Anglo-Russian Entente and Entente Cordial led to the formation of the Triple Entente, an alliance between Russia, France and Britain. Triple Entente included some off-alliances with Portugal and Japan as well.
Austria-Hungary announces the annexation of Bosnia - Herzegovina, which drew the attention of Russia, the Ottoman Empire, Britain, Italy, Serbia, Montenegro, Germany and France. The annexation strained relationships between Russia and Austria - Hungary.
Balkan League (Serbia, Greece, Montenegro and Bulgaria) against the Ottoman Empire. Victory for the Balkan states.
Bulgaria attacks Serbia and Greece after the end of the First Balkan War, because it was unhappy with the split of land. Romania and the Ottoman Empire joined Serbia and Greece. Result was the Treaty of Bucharest that gave land to Serbia, Greece, Romania and the Ottomans.
Serbia was left the only ally of Russia in the Balkan Peninsula.
Bosnian Serb nationalist youth named Gavrilo Princip, a member of Young Bosnia, assassinates Archduke Franz Ferdinand. In response, Austria-Hungary declares war on Serbia.