Relations with Yugoslavia have more often than not been troubled to the point of enmity. The problems existing between these two countries have deep historical roots that hinge primarily on the Bulgarian contention that Macedonia (since 1946 a federated republic of Yugoslavia) should be Bulgarian rather than Yugoslavian. After World War II, when both countries became communist, the Macedonian question was purposely deemphasized but, when the Soviet-Yugoslav split occurred in 1948, ideological differences paved the way for a renewal of the polemics on the Bulgarian irredentist claims. In the early 1970s the polemics were reduced to a minor level, and constructive talks leading to a rapprochement began to occur. The changed atmosphere was attributed to the state of relations between the Soviet Union and Yugoslavia but, for whatever reason, the climate of relations between Bulgaria and its western neighbor was considerably improved, and Bulgarian irredentism was submerged.
The European Conference for Security and Cooperation held in Helsinki in the spring of 1973 discussed the possibility of a freer exchange of people and ideas as well as a freer flow of information between Western European and Eastern European societies. The intensity of ideological polemics had diminished with increasing contacts between East and West, and the gap between the two social systems seemed narrower, especially in regard to economic planning and development. Bulgaria, however, publicly expressed doubts about importing anti-communist theories that might accompany the freer exchanges of people, ideas, and information.
In a plenum of the Central Committee of the Bulgarian Communist Party in July 1973, the party leaders touched on issues of international relations. The leaders pledged to continue a new policy of building goodwill and enhancing relations with noncommunist European states as well as with other developed capitalist states in all aspects of political, economic, cultural, and other relations. Bulgaria also sought to continue cultivating and developing friendly relations with nonaligned friendly countries in Asia, Africa, and Latin America. Consistent with this policy, it pledged to render assistance to these countries, especially where there were national liberation movements involved in active resistance to the established regimes.