Bogomils was a term used to refer to a medieval dualist sect that existed in Bulgaria and the Balkans. Synonyms for this term include Paulicians, Massalians, and Paternians. The Paulicians were an early Christian sect that was believed to have originated in Armenia, while the Massalians were a group of Christian ascetics in the 4th century who lived in Syria and Mesopotamia. The Paternians were a group of heretical Christians in the medieval era who were considered to be part of the Cathar heresy. These various groups are all linked by their adoption of a dualistic belief system that emphasized the struggle between good and evil.