In 1903 a coup d’état in Belgrade had overthrown the Obrenovic dynasty that had pursued a course of conciliation towards the Dual Monarchy, and replaced it with a regime dedicated to the expansion of Serbia through the liberation of Serbs under foreign rule— especially those in Bosnia. Five years later Austria formally annexed Bosnia-Herzegovina to facilitate her control over those provinces. The Serb government responded by creating an open ‘liberation movement’ for Bosnian Serbs with a covert terrorist wing, ‘the Black Hand’, trained and supported by elements within the Serb army. At the same time, Serbia, with Russian encouragement, took the lead in forming a ‘Balkan League’ with Greece, Bulgaria, and Montenegro, dedicated to the final expulsion of the Turks from the peninsula. Their opportunity came in 1912, when the Turks were engaged in defending their territories in Libya against an attack by Italy, whose government had grandiose ambitions (anticipating those of Mussolini a generation later) to restore the glories of the Roman Empire. In the First Balkan War of that year the Balkan allies drove the Turks from the entire peninsula except a bridgehead round Adrianople. A second war was fought the following year between the victorious allies over the division of the spoils.
As a result of these two wars, the territory and population of Serbia were doubled and her ambitions hugely encouraged. But in Vienna the reigning emotions were fear and frustration: fear at the apparently unstoppable march of Serbia, with all the encouragement this gave to Slav dissidents in both halves of the Monarchy; and frustration at their inability to do anything about it. Then on 28 July 1914 the heir to the Habsburg throne, Archduke Franz Ferdinand, was assassinated in Sarajevo, the capital of Bosnia-Herzegovina, by Gavril Princip, a teenage terrorist trained and armed by the Serb-sponsored Black Hand.