At the Congress of Berlin (13 June – 13 July 1878), the major European powers revised the territorial and political terms imposed by the Russian Empire on the Ottoman Empire by the Treaty of San Stefano (March 1878), which had ended the Russo-Turkish War of 1877–1878. The Congress was the result of escalating tensions; particularly British opposition to Russian hegemony over the Ottoman Empire in the Balkans, through the creation of a Russian-aligned 'Greater Bulgaria'. To secure the European balance of power in favour of its splendid isolation achieved after the Crimean War, Britain stationed the Mediterranean Fleet near Constantinople to enforce British demands. To avoid war, Otto von Bismarck, Chancellor of the newly formed German Empire, was asked to mediate a solution that would restore the Ottoman Empire's position as a counterbalance to Russian influence in the Mediterranean and the Balkans, in line with the principles of the 1856 Treaty of Paris.
Attended by delegates from Europe's then six great powers: Russia, Great Britain, France, Austria-Hungary, Italy, and Germany; the Ottomans as well as representatives of four Balkan states (Greece, Serbia, Romania and Montenegro), the Congress culminated in the Treaty of Berlin (13 July 1878). This agreement essentially dismantled the autonomous Greater Bulgarian State envisaged at San Stefano, and reorganised the borders of south-eastern Europe. The main results were the Austro-Hungarian forcible occupation of Bosnia and Herzegovina, the British de facto annexation of Cyprus under false pretenses, and the formal recognition of the self-declared independence of Romania, Serbia and Montenegro; allies of Russia in the previous war. While the settlement averted war, it exacerbated nationalist grievances in the Balkans and deepened the rivalry between Britain and Russia (The Great Game), contributing to long-term regional instability that foreshadowed the Balkan Wars and World War I.