Semi-Autonomous: The Eastern Orthodox Church in Bulgaria has deep roots, extending back to the 5th and 7th centuries when the Slavs and the Bulgars, respectively, adopted Byzantine Christianity in the period of the First Bulgarian Empire (681-1018).[1] Prior to this official conversion, Christianity had spread to the region during Roman and early Byzantine times.It bears the distinction of being the oldest Slavic Christian Church in the Orthodox communion.[2] Twenty years later, the 2021 census noted that 69.% of the population identified as Eastern Orthodox Christian (mainly the BOC).[3] The Bulgarian Patriarchate has within its jurisdiction 13 dioceses in Bulgaria and another two in Europe and North America.