to enter World War I on the side of the Central Powers.) France, on its part, occupied Tunisia in 1881. The results were first hailed as a great achievement in peacemaking and stabilization. However, most of the participants were not fully satisfied, and grievances regarding the results festered until they exploded into world war in 1914. Serbia, Bulgaria, and Greece made gains, but far less than they thought they deserved. The Ottoman Empire called at the time the "sick man of Europe", was humiliated and significantly weakened, rendering it more liable to domestic unrest and more vulnerable to attack. Although Russia had been victorious in the war that occasioned the conference, it was humiliated at Berlin, and resented its treatment. Austria gained a great deal of territory, which angered the South Slavs, and led to decades of tensions in Bosnia and Herzegovina. Bismarck became the target of hatred of Russian nationalists and Pan-Slavists and found that he had tied Germany too closely to Austria in the Balkans. In the long run, tensions between Russia and Austria-Hungary intensified, as did the nationality question in the Balkans. The Congress succeeded in keeping Istanbul in Ottoman hands. It effectively disavowed Russia's victory. The Congress of Berlin returned to the Ottoman Empire territories that the previous treaty had given to the Principality of Bulgaria, most notably Macedonia, thus setting up a strong revanchist demand in Bulgaria that in 1912 led to the First Balkan War in which the Turks were defeated and lost nearly all of Europe. As the Ottoman Empire gradually shrank in size, military power, and wealth, many Balkan Muslims migrated to the empire's remaining territory in Balkans or to the heartland in Anatolia. Muslims had been the majority in some parts of Ottoman Empire such as the Crimea, the Balkans, and the Caucasus as well as a plurality in southern Russia and also in some parts of Romania. Most of these lands were lost with time by the Ottoman Empire between the 19th and 20th centuries. By 1923, only Anatolia and eastern Thrace remained as the Muslim land. İstibdat Era, 1878–1908 1878–1908 Abdul Hamid II The reign of Abdul Hamid II was pejoratively referred to as istibdad (despotism). His reign struggled with the culmination of 75 years of change throughout the empire and an opposing reaction to that change. He was particularly concerned with the centralization of the empire. His efforts