Any member of a religious sect that flourished in the Balkans during the 10th–15th centuries. Founded by a 10th-century Bulgarian priest traditionally known as Bogomil, the sect's beliefs arose from the possible fusion of dualistic doctrines imported mainly from the Paulicians (a sect of Armenia and Asia Minor) and a local Slavonic movement aimed at reforming the new Bulgarian Orthodox church. Its central teaching was that the visible, material world was created by the Devil. The Bogomils taught a Docetist Christology instead of the traditional doctrine of the Incarnation, rejected the Christian conception of matter as a vehicle of grace, and repudiated the whole organization of the Orthodox church. They were active missionaries who lived rigorously ascetic lives. During the 11th–12th centuries Bogomilism spread over many European and Asian provinces of the Byzantine Empire; it also spread into western Europe, where it contributed to the formation of the Cathar heresy. In Bulgaria it remained a powerful force until the late 14th century. With the Ottoman conquest of southeastern Europe in the 15th century, its influence declined. See alsodualism.