From the ninth until the fourteenth century Bulgaria was a dominant force in the Balkans because of its aggressive military tradition and strong sense of national identity. The chief rival and neighbor the Byzantine Empire left a lasting political imprint on two Bulgarian empires as it competed with them for regional domination. Marking the deterioration of both the Byzantine and the Bulgarian political structures the fall of Constantinople to the Ottoman Turks in 1453 began four centuries of Turkish suppression of Bulgarian cultural and political institutions.
By the eighteenth century however weakening Ottoman control allowed a Bulgarian cultural revival. In the next century Western political ideas gradually combined with the reborn Bulgarian national consciousness to form an independence movement. The movement was complicated by internal disagreement on aims and methods the increasing weakness of the Ottoman foothold in Europe and the conflicting attitudes of the major European powers toward Bulgaria. Russia gained distinction as Bulgaria's protector by driving out the Turks in 1877 but France and Britain curbed Russian power in the Balkans by forcing establishment of a limited autonomous Bulgarian state under Turkish rule. The instrument of that limitation the Treaty of Berlin revived longstanding Bulgarian territorial frustrations by placing the critical regions of Macedonia and Thrace beyond Bulgarian control. Both of those disputed regions had substantial Bulgarian populations. During the next sixty years Bulgaria would fight unsuccessfully in four wars in a variety of alliances to redress the grievance. None of the four wars brought substantial new territory to Bulgaria.
Beginning in 1878 Bulgaria was nominally ruled by members of West European royal houses under a parliamentary form of government. Prime Minister Stefan Stambolov unified the country during its first decade but extremist political parties exerted substantial influence from the beginning. Between 1878 and the declaration of full independence in 1908 Bulgaria passed through a period of peaceful modernization with expansion in industry science education and the arts. Modernization and industrialization sowed the seeds of class conflict however nurturing strong socialist and agrarian opposition parties in the decades that followed independence.
The period between 1912 and 1944 was full of irredentist wars and internal political turmoil. By 1900 Serbia and Greece were the major territorial rivals but a World War I alliance with Germany gained Bulgaria little advantage over them. After the war the agrarian reform government of Aleksandur Stamboliiski had failed to unite the country by 1923. The series of unstable factions and forms of government that followed Stamboliiski was broken only by Bulgaria's participation as an Axis ally in World War II. Again no territory was gained but World War II brought Soviet occupation the end of the monarchy and forty-one years of unbroken communist rule beginning in 1946. During that entire period Bulgaria was the closest East European imitator of Soviet internal and foreign policy. The years 1944 through 1989 were a time of collectivization heavy industrialization drastic restriction of human rights and close adherence to Soviet Cold-War policy.