The Bosnian Crisis, also known as the Annexation Crisis (German: Bosnische Annexionskrise, Turkish: Bosna Krizi; Serbo-Croatian: Aneksiona kriza, Анексиона криза) 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. Although the crisis ended with what appeared to be a total Austro-Hungarian diplomatic victory, it 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. 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.
The mid-1870s witnessed a series of violent rebellions against Ottoman rule in the Balkans, and equally violent and repressive responses from the Ottoman Empire. The Russian Tsar, Alexander II, wanting to intervene against the Ottomans, wanted 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 Ottoman Empire. As compensation for this support, Russia agreed to Austria-Hungary's control over Bosnia-Herzegovina.
Shortly thereafter, the Russians declared war, and, after a few setbacks, drove the Ottomans relentlessly back to within a few miles of Constantinople. What stopped the Russians from driving the Ottomans 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 in the Budapest Convention and declared that Bosnia-Herzegovina would be jointly occupied by Russian and Austrian troops.
The Treaty of San Stefano was overturned by the 1878 Treaty of Berlin. Under article 29, Austria-Hungary received special rights in the Ottoman Empire's provinces of Bosnia-Herzegovina and the Sanjak of Novi Pazar. Article 25 stated that "The provinces of Bosnia and Herzegovina shall be occupied and administered by Austria-Hungary" and continued "Austria-Hungary reserves the right to maintain garrisons and to have military and trading roads over the whole area of that portion the Sanjak of Novi Pazar of the ancient Vilayet of Bosnia."
The Bosniak-dominated Sanjak of Novi Pazar separated Montenegro from Serbia and prevented the geographic and political union of these two states which were often closely aligned. The Austrian occupation of the Sanjak was also significant because it provided Austria-Hungary with a staging area for possible future expansion towards the Aegean port of Salonika in Ottoman-controlled Macedonia.
Austria-Hungary exercised its legal rights, taking firm control of Bosnia-Herzegovina and jointly occupying the Sanjak of Novi Pazar together with the Ottoman Empire. The Treaty of Berlin allowed for sole Austrian occupation of Bosnia-Herzegovina, but did not specify a final disposition of the provinces. This omission was addressed in the Three Emperors' League treaty of 1881, where both Germany and Russia endorsed Austria's right to annex Bosnia-Herzegovina. A bilateral commercial treaty between Austria and Serbia in the same year had a secret annexe, stating that "Serbia 'would not permit any political, religious or other intrigue to be directed from her territory against the Austro-Hungarian monarchy, including Bosnia, Herzegovina and the Sanjak of Novi Pazar'". However, by 1897, under the new Tsar, Nicholas II, the Russian Imperial government had managed, again, to withdraw its support for Austrian annexation of Bosnia-Herzegovina. The Russian Foreign Minister, Count Michael Muraviev, stated that an Austrian annexation of Bosnia-Herzegovina would raise "an extensive question requiring special scrutiny". Serbia allowed their obligations under the commercial treaty of 1881 to lapse in 1899.
In 1903 King Alexander Obrenovic of Serbia was assassinated in a coup and the pro-Russian Karađorđević dynasty came to the throne. Power shifted to elements widely interested in expansion into Bosnia. The new Serbian government wanted to take over the Sanjak of Novi Pazar and Bosnia-Herzegovina from the Austro-Hungarians. Relations between Serbia and Austria-Hungary gradually deteriorated. However, Russia's ability to support Serbia was greatly reduced following military humiliation in the 1905 Russo-Japanese War and the ensuing internal unrest.
By 1907, Austro-Hungarian Foreign Minister Alois Aehrenthal began formulating a plan to solidify Austria-Hungary's position towards Serbia through annexation of Bosnia-Herzegovina. His opportunity came in the form of a letter from Russian Foreign Minister Alexander Izvolsky – proposing Austrian annexation of the provinces as part of a deal to secure better access to the Turkish Straits for Russian naval vessels – and a subsequent meeting at Buchlau castle in Moravia, Austria-Hungary.
Under the Treaty of Berlin, the Ottomans controlled the Dardanelles strait connecting the Mediterranean and the Black Sea. The Treaty prohibited the passage of any warships from any country into or out of the Black Sea. This treaty bottled up the Black Sea Fleet, a major portion of the Russian Navy, making it useless in the Russo-Japanese War of 1904-1905 when it was urgently needed. Izvolsky wanted this changed to allow the passage of Russian ships through the straits. Aehrenthal wanted full control of Bosnia-Herzegovina. Austria-Hungary had administered the provinces since 1878 but the Ottoman Empire remained the nominal legal owner. Aehrenthal concocted a grand diplomatic deal that proposed major benefits for both sides. Austria would gain full ownership of Bosnia with Russian approval. The Ottomans would regain full control of the territory known as the Sanjak of Novi Pazar, and monetary compensation. Russia would get the right of passage for its warships through the Straits. Serbia would get nothing.
Before approaching the Russians, Aehrenthal met with Austrian officials and won the approval of Emperor Franz Joseph I. On September 15–16 Aehrenthal and Izvolsky held a secret meeting. No record was kept – and afterwards both sides remembered it very differently. Aehrenthal assumed he had full Russian approval for his scheme, but he did not give out planned dates. Izvolsky assumed he would be informed before any actual move happened. Aehrenthal vaguely informed all the major countries but gave no details. The world was astonished on October 6, 1908, when a press release in Vienna announced that Bosnia was fully annexed. Inside Austria there was general approval except in Czech areas – that minority strongly felt its demands had been deliberately ignored.
Aehrenthal had expected wide European approval and instead he faced a hostile volcanic eruption from every direction. Izvolsky vehemently denounced the action and demanded an international conference on Bosnia. After decades of low-level activity, pan-Slavic forces inside Russia mobilized in opposition. Mass demonstrations broke out across the continent. Rome took advantage of the situation by reversing its friendship with Vienna. Berlin officials were surprised and appalled. The British were especially angry, denouncing the violation of an international agreement signed by both Austria and Britain. France denounced the scheme. The Ottomans were surprised by the unexpected development, but was quieted by the cash payment. By far the angriest reaction came from Serbia, which called for revenge, and began setting up secret guerrilla bands, plotting insurrection and other clandestine activities in the annexed Bosnia and its capital, Sarajevo.