Nation of SE Europe, in the E Balkans, with the Black Sea on the E, Serbia and Montenegro and Macedonia to the W, Romania to the N, and Greece and Turkey to the S. Its territory is roughly the same as the ancient land s of Moesia and Thrace. Bulgar tribes from the Volga River region settled in the territory in a.d. 679–80 and by the ninth century had merged with the Slavs they had subjugated. The first Bulgarian Empire, established by Khan Asparuhk, lasted from 681 to 1018 and for a time threatened the power of the Byzantine Empire. It reached its peak under Simeon I (893–927) who took the title of czar. However, attacks by a revived Byzantine Empire resulted in Bulgaria’s annexation in 1018. Bulgaria recovered its power, and in 1186 the second empire arose under Czar Ivan I (Ivan Asen). It reached its height under Ivan II (1218–41) when its rule extended over almost all the Balkan Peninsula except Greece. This empire ended in 1396 when the Ottomon Turks defeated a Christian army at Nikopol. Bulgaria remained under the Ottoman Empire until 1877. At that time an unsuccessful revolt brought such atrocious reprisals by the Turks that Russia entered the struggle on Bulgaria’s side, and with success. The result was the Treaty of San Stefano in 1878, which greatly enlarged Bulgaria and made it an autonomous principality. Fearing the sudden growth of Russian power, other European nations at the Congress of Berlin later in 1878 forced a number of changes in the treaty. Among them was the division of Bulgaria into three parts, none of them entirely independent. In 1885 Prince Alexand er, ruler of the more autonomous part of Bulgaria, annexed present southern Bulgaria, then known as Eastern Rumelia, and repelled an attack by Serbia. When there was a revolt in the Ottoman Empire in 1908, Prince Ferdinand proclaimed full independence and made himself czar. In 1912 and 1913 two short wars were fought by the Balkan nations over the land s of the faltering Ottoman Empire. Bulgaria was victorious at first but was defeated in the end and lost land to all her enemies by the Treaty of Bucharest in 1913. Bulgaria entered World War I in 1915 on the side of Germany and her allies, the Central Powers. Her subsequent defeat resulted in the Treaty of Neuilly of 1919, by which Bulgaria ceded part of western Thrace to Greece, several border areas to Yugoslavia, and paid reparations. In the interwar period, Boris III established a military dictatorship in 1934, and in 1941 joined Germany in World War II. Again on the losing side, in 1946 Bulgaria fell into the Soviet orbit with a communist government and membership in the Warsaw Pact of the Soviet-dominated nations of eastern Europe. Long-time communist leader, Georgi Dimitrov, ruled as premier from 1946 to 1949. Most of Bulgaria’s farm land was collectivized in 1958. From 1978 through 1989, Todor Zhivkov, as head of the Communist Party, was the most powerful man in the country. During this time, the country became one of the more prosperous in eastern Europe, with agricultural reform allowing private ownership of small plots and growth in the industrial sectors. The shift to a market economy after the collapse of communism in 1989 has been slow as the renamed Communist Party (now the Bulgarian Socialist Party) continued to control the government of newly democratic Bulgaria. In 2001, the Bulgarian monarchy made a return when former king Simeon II was elected prime minister. Bulgarias’s Turkish minority was represented in the government for the first time, and President Georgi Parvanov has encouraged Bulgarians to be more tolerant of Turkish-Bulgarians. Bulgaria was accepted into NATO in 2004, and has applied for membership in the European Union. Sofia, a Bulgarian town since 809, has been the capital since 1879.