The Bulgarian empire, after reaching its peak under Simeon in the early tenth century, has declined under Tsar Peter, his son and successor.

The Bogomil heresy meanwhile gains adherents in Bulgaria toward the middle of the tenth century.

The Bogomils' central teaching, based on a dualistic cosmology, is that the visible, material world was created by the devil.

Thus, they deny the doctrine of the incarnation and reject the Christian conception of matter as a vehicle of grace.

They reject Baptism, the Eucharist, and the whole organization of the Orthodox Church.

The moral teaching of the Bogomils is as consistently dualistic.

They condemn those functions of man that bring him into close contact with matter, especially marriage, the eating of meat, and the drinking of wine.

Even their fiercest opponents invariably acknowledge the moral austerity of the Bogomils.