As decided by the Berlin Congress (1878), Austria-Hungary received the right to occupy Bosnia and Herzegovina. In summer 1908, the outbreak of the Young Turk Revolution brought the possibility of full restoration of Ottoman sovereignty over these two provinces.
This was the main reason for the decision of Vienna to annex both provinces. On 6th October, 1908, the annexation was proclaimed that led to a very dangerous international crisis, which lasted from October 1908 to the end of March 1909.
During this crisis, Serbia raised claims for territorial compensations, although, in the light of the international law, had no right to place such demands. Germany supported decisively his ally, what led to the diplomatic victory of Vienna and to the rejection of the Serbian demands.
However, this result was only a Pyrrhic victory of the Habsburg monarchy. The relations between Vienna and St.
Petersburg irreparably damaged and Austria-Hungary fell into international isolation.