BOGOMILI (AMICI DI DIO). — Christian heretical sect that appeared in Bulgaria between the first and second halves of the 10th century. The B. derive their name from their leader, the priest Bogomil (in Bulgarian bogumil, “dear to God”). Although the origins of Bogomilism are still obscure, it is certain that this “haeresis Bulgarorum” originated from various earlier heresies, especially the Manichaeans, Paulicians (in Thrace and Macedonia, 8th century), Byzantine iconoclasts and, more immediately, the Messalians, according to the testimony of Euthymius (PG 132, 1290). The sect soon spread throughout Bulgaria and, under various other names (Cathars, Bulgarians, Albigensians), throughout the Balkans and other European regions, as far as Russia.
At the foundation of the doctrinal system lies a dualistic-Gnostic principle of a distinctly Manichaean character, which admits God as creator of everything that is spiritually good and eternal both in man and in the world, and the Devil as author of evil, of the contingent, and of the material and corporeal. Rejecting the Old Testament, a large part of the Sacraments, especially Marriage, and sacred images, and denying Purgatory, the B. made worship consist in adoring God “in spirit and truth” and in an austere ascetic life.
The movement, not immediately suppressed, experienced periods of great expansion and periods of stagnation: expansion under Peter (927–69), in Bulgaria and later in Bosnia and throughout the Balkans; stagnation as early as 1019 with the establishment of Constantinopolitan rule and thereafter with the fierce persecutions directed against them by bishops and councils (1211, 1325, 1360, etc.), and by Bulgarian emperors and kings in the 12th–14th centuries. Preachers and missionaries, Dominicans and Friars Minor, were sent by the Popes in the 13th and 14th centuries, especially to Bosnia, where they also achieved important successes, such as the conversion, in 1402, of 50,000 dissidents through the work of the Conventual Franciscans (L. Wadding, Annales Ord. Min., an. 1402, Quaracchi 1931, n. 11). But the strongest opponent of the B. in the doctrinal field was the great theologian Cosmas, a Bulgarian priest (and bishop) of the 10th century, who unmasked the founder and refuted his doctrines one by one, calling the people back to the true faith. The patriarch Theophilus and the monk Theodore also engaged in a merciless struggle against the B. in the 14th century. But, given the fanaticism of its adherents, the error spread to other parts of Europe as well, and B. were found, especially confused with the Cathars or Albigensians with whom they eventually became identified, in Dalmatia, Italy, France, Spain, Germany, England and elsewhere. The Slavic Bogomilist heresy, with its connections, influenced all the heretical movements of the West before the advent of Luther.