[7] Christianity was adopted — in its Byzantine Orthodox form, then still part of a United Church, from the neighbouring Byzantine Empire — as an ideological and ethnic homogeniser around 864 by the khan Boris-Mihail; the Christianisation of Bulgaria was largely a political expedient which granted the Bulgarian khans the same status as other European monarchs, but it also met considerable opposition, especially from the aristocracy and even from Boris-Mihail's son and heir to the throne, Vladimir-Rasate, who tried to suppress Christianity and revert to paganism as he saw the former as a tool of political yoke from Byzantium.
[8] Both Bogomilism and Hesychasm were highly spiritual, mystical and meditative doctrines and practices, favouring the inner (esoteric) path to God and organised around monasticism, but while the former was dualistic, with an accentuated distinction between spirit and matter, the latter was monistic and spread to Bulgaria largely as a reaction to the former.
[10] The need to persist under Ottoman domination strengthened the conservatism of the Bulgarian Orthodox Church and insulated it from external influences, so that it remained untouched by the ideas of Protestantism when the Protestant Reformation was spreading athwart continental Europe.
[10] At the same time, however, this situation favoured a tendency to secularisation and conformism towards the state, so that the Orthodox Christian clergy lost spiritual and moral authority for many Bulgarians.
[11] In 1870, the Ottoman sultan Mehmed VI officially set up the Bulgarian Orthodox Exarchate, while the Patriarchate of Constantinople declared it schismatic and an ethno-nationalist heresy.
[12] The role of the church in society began to be questioned by the emerging intelligentsia, and especially by socialist thinkers, most of whom were teachers and state employees or white collar workers.
[12] One of the earliest Marxists, Dimitar Blagoev (1856–1924), while recognising the important role that the church had in past Bulgarian history, attacked it because, according to him, in modernity it had become "a tool of the bourgeoisie" and a network of the latter's "political clubs".
[12] At the end of the World War II, in 1943, the government of Bulgaria signed an agreement with National Socialist Germany and began implementing the Final Solution against Bulgarian Jews — their deportation to death camps.
[13] Over the next four years, the communists, sponsored by the Soviet Union, ousted and banned all opposition parties, took full power and undertook a transformation of society according to the Stalinist model.
[13] At the same time, during the period of full implementation of Stalinism, religiosity was in fact restricted, and the Bulgarian Orthodox Church became a tool of the interests of the communists in domestic and foreign politics.
[13] After the establishment of the communist republic, a number of Orthodox Christian priests were arrested and tried by "people's courts"; some of them were condemned to life imprisoned or to death.
[13] From 1945, only civil marriage was recognised by the state, religious activities were banned in the armed forces, so were prayers and religion classes in schools, while all restrictions on atheism and free thinking were removed.
[14] In general, communist Bulgaria, while taking the Soviet Union as a model, never imitated Bolshevik extreme methods of forbidding religion completely and destroying places of worship.
[14] Georgi Dimitrov, who was communist leader from 1946 to 1949 and was born in a Protestant family, in a 1946 speech on the occasion of the thousandth anniversary of John of Rila, the patron saint of Bulgaria, praised the Orthodox Church for its historical role and for preserving national identity and culture.
[16] The transformation of Bulgarian society after the fall of communism has also led to the spread of Eastern religions, various new religious movements, the newest denominations of Protestantism, and Restorationism.
[17] A new religious movement indigenous to Bulgaria is Dunovism, a form of Neo-Theosophy also known as the Universal White Brotherhood, which was founded in the early 20th century by the spiritual teacher Peter Deunov (1864–1944) and has undergone a great revival in its home country and an international propagation since the 1990s.
[16] The late 20th and early 21st century have also seen the appearance of Neopagan religious movements in Bulgaria, including Slavic Rodnovery (often with elements of Turco-Mongol Tengrism), Celtic Druidry, and Thracian Hellenism.
[1] Since the 1990s, Bulgarian society has witnessed the spread of Eastern religions and new religious movements, including Krishnaism, yoga schools and the Baháʼí Faith.
[22] A peculiar new religious movement that is indigenous to Bulgaria itself and has experienced a strong revival since the 1990s is Dunovism, also known by its collective name, the Universal White Brotherhood, founded in the early 20th century by Peter Deunov.
[22] Slavic Rodnovery (often with Turko-Mongol Tengrist elements), Celtic Druidry, and Thracian Hellenism are Neopagan movements present in Bulgaria.