In 1989, the wave of democratization in Eastern Europe also reached Bulgaria.

Beginning in 1954, Todor Zhivkov of the Bulgarian Communist Party successively served as the first secretary, general secretary, chairman of the Council of Ministers, and chairman of the State Council of the People's Republic of Bulgaria. During his 33-year term of office, Bulgaria was completely loyal to the Soviet Union; Zhivkov was considered one of the most conservative leaders in Eastern Europe.

After Gorbachev became general secretary of the Soviet Union in 1985, he began to implement a series of reforms; Zhivkov likewise focused on promoting Gorbachev's reform model in the country. However, the two subsequently disagreed on the model to be adopted. In 1989, as domestic political and economic crises emerged, the people's demands for reforms increased. As a result, on November 10th, Zhivkov was forced out of his positions as first secretary of the Bulgarian Communist Party Central Committee, as member of the Politburo, and as chairman of the State Council. This was labeled a "palace coup" by the Bulgarian media. Zhivkov's ouster accelerated the build-up of protests in Bulgarian society. On November 18th, the Bulgarian opposition held its first mass rally of nearly 100,000 people, with slogans and catch-phrases such as "Democracy", "Openness", "Pluralism" and "Reform".

The following year, the People's Republic of Bulgaria shifted to a multi-party system; the Bulgarian Communist Party abandoned one-party rule, and reorganized itself into the Bulgarian Socialist Party. In November, the country's name was officially changed to the "Republic of Bulgaria", as it remains today.

References: [中共中央黨史和文獻研究院("Party History and Literary Research Institute of the CCP Central Committee")(Chinese)] (http://www.dswxyjy.org.cn/BIG5/n1/2019/0617/c427165-31161453.html); [Wikipedia: "Todor Zhivkov"] (https://en.wikipedia.org/wiki/Todor_Zhivkov); [Wikipedia: "Bulgarian Communist Party"] (https://en.wikipedia.org/wiki/Bulgarian_Communist_Party)