Bogomilism is a Gnostic religio-political sect founded in the First Bulgarian Empire by the priest Bogomil during the reign of Tsar Peter I in the 10th century.

It most probably arose in what is today the region of Macedonia as a response to the social stratification that occurred as a result of the introduction of feudalism and as a form of political movement and opposition to the Bulgarian state and the church.The Bogomils call for a return to early Christianity, rejecting the ecclesiastical hierarchy, and their primary political tendencies are resistance to the state and church authorities.

This helps the movement spread quickly in the Balkans, gradually expanding throughout the Byzantine Empire and later reaching Kievan Rus', Bosnia, Dalmatia, Rascia, Italy, France.The Bogomils are dualists in that they believe the world was created not by the Abrahamic God, but by an evil demiurge — the Devil.

They do not use the cross nor build churches, preferring to perform rituals outdoors.