Political map of Europe & the Mediterranean 20 October 1878 (Aftermath of the Great Eastern Crisis): The Russian victory over Turkey (Russo-Turkish War (1877–1878)) alarmed the other Great Powers (Great Powers). At the Congress of Berlin (Congress of Berlin), they overruled San Stefano (Treaty of San Stefano). Russian gains were diminished, Bulgaria was divided into two much smaller states (Eastern Rumelia), Britain was granted control of Cyprus (Cyprus Convention), and Austria was allowed to occupy Bosnia-Herzegovina (Austro-Hungarian occupation of Bosnia and Herzegovina).