The origins and nature of the Bosnian Church have been subjects of wide debate. One view holds that it evolved from the Bogomil movement into a national church displacing Catholicism as the established religion of Bosnia in about 1250. The Bogomil were also known as Paterenes or Kudugers at this time. A second view rejects the dualist nature of the Church of Bosnia but admits the presence of a dualist movement in the religious life of medieval Bosnia and its potential influences on the church.
According to this view, the Church emerged as a reaction to the Hungarian Crusades, but had deep roots in an earlier Catholic monastic tradition developed in isolation from both East and West. This newly formed fusion Church would have abandoned some of its Dualist beliefs and practices on its way to becoming an established ecclesiastical body. A creation of a rival Church with a Slavic liturgy would prevent Rome from taking firm control. Concurrently, a Dualist sect such as the Bogomil might have remained independent from the Bosnian Church but still capable of influencing members of the church and perhaps even reviving Dualist concepts in its theology.
The first signs of an organized Bosnian Church appear in 1167, at an assembly of Cathars near Toulouse, France, where the faithful were informed of “Pope”Nikita and the existence of the Bosnian Church. In 1199, Pope Innocent III received the alarming report that Ban Kulin of Bosnia, who sought independence from the suzerainty of Hungary, had succumbed, along with his family and 10,000 Christians to the‘heresy’.
A year later, Ban Kulin was accused of granting asylum to Bogomil expelled from Dalmatia. Ban Kulin insisted that they were actually Catholics, though they kept their faith. However, with the threat of a papacy-backed Hungarian attack, Ban Kulin sent several suspected priors of Bosnian monasteries to Rome for a profession of faith and to accept a papal inspection of the religious affairs of Bosnia. The priors promised to bring altars and crosses into the churches, to read from the Old as well as the New Testament, to observe fasts and church services true to the Catholic Church and not to admit Manichaeans and other heretics into their orders. The measures of the anti-Bogomil Council of 1211 failed to suppress the neighboring Bulgarian Church. The Bulgarian Tsar, Ivan Asen II (1218-41), the most powerful monarch in the Balkans, released the Bulgarian Church from its allegiance to the Roman See in 1235, which directly threatened the Latin Kingdom of Jerusalem. Pope Gregory IX prevailed upon the Hungarian King Bela IV to launch a Crusade against Bulgaria, which was ‘infected by heretics’. This projected Crusade was foiled by the diplomacy of Tsar Asen.
From the middle of the 13th century, Bosnia was considered the center of the heretic movement in Europe. The early 14th century witnessed the increasing importance of the Bosnian Church in the volatile political affairs of Bosnia. Though not an official state religion, the Bosnian Church had the support of powerful Bosnian nobles and was active in the Bosnian Court. In 1325, Pope John XXII issued a complaint to the Bosnian Ban and the Hungarian king that numerous heretics from different states were streaming into Bosnia. The report was written at the same time as the Inquisition was extinguishing the last visible traces of Catharism in the Languedoc and Lombardy, and testifies to the papal distress with Bosnia for giving refuge to persecuted Cathars and becoming a center of the so-called ‘heretical’Diaspora
The Medieval Gnostics: The Bogomil by Judith Mann