From its earliest history Bulgaria was in continual conflict with its Balkan neighbors. The area that eventually became Bulgaria was the object of regional disputes as early as the fourth century B.C. Later, when that area was taken over by the Slavs in the sixth century A.D. and the Bulgars in the seventh, a state evolved that proceeded to encroach on the territory of the mighty Byzantine Empire itself. Despite successful raids and conquests during the periods of the First Bulgarian Kingdom and the Second Bulgarian Kingdom, Bulgaria was eventually reduced to subject status by the Byzantines and later by the Ottoman Turks. During Turkish rule the country was not only under constant attack by neighbors but was also utilized by the Turks as a base for Turkish expansion. When Bulgaria was finally liberated from the Turks by the Russians, irredentism and regional rivalry became the prime focus of its foreign policy. Macedonia, a much-valued land throughout Bulgarian history, became the major object of Bulgaria's irredentist campaigns, although eventually most of the land reverted to Serbia and was later incorporated into Yugoslavia. Macedonia, in addition to Thrace, which was valued because it provided access to the sea, was the primary motive for Bulgaria's role not only in the two Balkan wars of 1912 and 1913 but also in the two world wars.
Bulgaria was not only struggling for power throughout its history; it was also a pawn in the power struggles of the so-called great powers. Before the Christian era the area was conquered first by Greece and later by Rome and was influenced strongly by both of these early cultures. Later, when the Slavs and Bulgars succeeded in forming a united state, the country was still besieged by both Byzantium and Rome. Although the Romans eventually lost their hold over Bulgaria, the Byzantine Empire took both political and religious control of the country for two centuries. When Bulgaria managed to reassert its autonomy in the time of the Second Bulgarian Kingdom, independence was short lived, and the country again fell under alien control, this time to the Ottoman Turks. The Turks dominated Bulgaria for five centuries, until liberation by the Russians temporarily gave the country full sovereignty. Before each of the two world wars of the twentieth century, Bulgaria was actively courted by both sides as a potentially strategic ally. Realizing Bulgaria's territorial aspirations, Germany played upon Bulgarian irredentism in order to gain its collaboration in the wars, and both times Bulgaria emerged on the losing side. When World War II ended for Bulgaria in 1944, it fell under Soviet influence, where it has remained ever since.