The Bosnian Crisis, also known as the Annexation Crisis (; ) or the First Balkan Crisis, erupted on 5 October 1908 when Austria-Hungary announced the annexation of Bosnia and Herzegovina, territories formerly within the sovereignty of the Ottoman Empire but under Austro-Hungarian administration since 1878. This unilateral action—timed to coincide with Bulgaria's declaration of independence from the Ottoman Empire on 5 October—sparked protestations from all the Great Powers and Austria-Hungary's Balkan neighbors, Serbia and Montenegro. In April 1909, the Treaty of Berlin was amended to reflect the fait accompli and bring the crisis to an end. The crisis permanently damaged relations between Austria-Hungary and its neighbors, especially Serbia, Italy and Russia, and in the long term helped lay the grounds for World War I. Although the crisis ended with what appeared to be a total Austro-Hungarian diplomatic victory, the crisis destroyed any remaining ability for Austria and Russia to cooperate in the Balkans and damaged Austrian relations with Serbia and Italy. Austro-Serbian relations – harmed by the annexation's inflaming of Serbian nationalists – continued to be strained to the point of declaring war on each other in 1914. Background The mid-1870s witnessed a series of violent rebellions against Ottoman rule in the Balkans, and equally violent and repressive responses from the Turks. The Russian Tsar, Alexander II, wanting to intervene against the Ottomans, sought and obtained an agreement with Austria-Hungary. In the Budapest Conventions of 1877, the two powers agreed that Russia would annex Bessarabia, and Austria-Hungary would observe a benevolent neutrality toward Russia in the pending war with the Turks. As compensation for this support, Russia agreed to Austria-Hungary's control of Bosnia-Herzegovina. Shortly thereafter, the Russians declared war, and, after a few setbacks, drove the Turks relentlessly back to within a few miles of Constantinople. What stopped the Russians from driving the Turks completely out of Europe was the willingness of the other great powers, particularly Britain and Austria-Hungary, to enforce an earlier treaty, the London Straits Convention of 1841, which stated that the Straits of Constantinople would be closed to warships during time of war. This had the effect of bottling up the Russian fleet in the Black Sea, but would be worthless if Russian troops gained control of the straits by land. After their victory in the war, the Russians then imposed the Treaty of San Stefano on the Ottomans, which, in part, reneged on pledges made