How Bulgaria became Orthodox
A fragment of Milan's Book "Dualistic heresies of the Middle Ages" In the 9th-10th centuries, the religious influence of the Byzantine Empire spread to the Balkans and led to the appeal of the Bulgarian Khanate to Orthodoxy. Its ministers and preachers had to face two dangers: the old paganism, for which the local population stubbornly held, and with new Christian heresies, is primarily by Pavlikianism.