In the medieval Croatia & Bosnia, appeared a gnostic movement known as Bogumilism. They called themselves only a "Christians" or "Krstjani" (in croatian language.) Situated beettwen two, also Christian, religions (Chatolic & Orthodox) this gnostics gave specific emphasis to the spiritual development of the medieval Europe during the three centuries.
Bogomil, i.e. Paterine heresy also took hold in Dalmatia (Southern Croatia) towards the end of the 12th century. historycal sources which mention heretical movements refer to the cities of Split, Trogir and Zadar, but the mainstay of the Bogomilism was otside of the cities, in the free spaces of ancient folk culture. at the time the Paterine - Bogomil heresy spread in the several areas inhabited by the South Slavs. In Serbia (Orthodox Christianity) was fiercly persecuted by Stephan Nemanja, the grand zupan. The Bogomils opposed the egsistence of a church as a fixed organisation; they were also against the church possessing properthy and compulsory tithes. The original Bogomil teaching preached disobeance to rulers and masters. Judging by treatise "Besedi na jeres" (On Heresy), written against the Bulgarian Bogomils by Presbyter Cosma (about 972), this gnostic movement opposed all forms of rule, violence and slavery, but it would be difficult to establish with what specific ideological platform it reaches the dalmatian cities. Here the socio-political edge of Bogomil teaching was probably dulled to a considerable extent. Research into the beginnings of the Bogomil penetration into Dalmatia leads us to Zadar. Thomas the Archdeacon says that the citizens of Zadar scorned the teaching of the Chatolic religion and they let themselves be besmirched by the heretical plague.
Historical record preserve the names of two dalmatian heretics, the brothers Aritsodes and Matthew Zorobabel, who propagated the Bogomil teaching - first of all in Zadar. They were then probably probably banished from the citiy and settled in Split, where they became the leaders of the heretical movement. Aristodes and Matthew maintained good ties with Bosnia, where bogomilism had become the official religion during the rule of Ban Kulin. many citizens of Split joined the heretics but the Church soon reacted harhsly. The Bogomils were banished from the citty. The same fate befell them in Trogir.
A letter writen in October 11, 1200, by Pope Innocent III to king Emeric, discloses that the banished Dalmatian heretics found refuge in Bosnia where they were recived warmly by Ban Kulin. " We have found out ", wrote the Pope, " that the nobleman, Ban Kulin of Bosnia, has given shelter and, even more, obvious protection to a considerable number of Bogomils recently banished from Split and Trogir by our brother, the Archibishop; he has given his land and himself to their wickedness and paid them the same respect as Chatolics, and even more than Chatolic, calling them Christians ". A year earlier Vukan Nemanjic had informed the Pope that Kulin had joined the new heresy with ten thousand people. the eventual fate of Aristodes and Matthew, who were also said to be " ..versed in Latin and Slavonic books ", is not known. Aristodes may have been the same person cursed, under the name of Rastudije, at the synod of St. Sava: " Curse upon Rastudije of Bosnia... and all... Christian man and women who do not venerate the sacred icons and the holy cross". If tis was a really the case, then Aristodes of Zadar became the first head (djed) of the bosnian Bogomils after having been banished from Split.
A western record from 1223 mentions an anti-pope " on the frontiers of the Bulgaria, Croatia and Dalmatia, near the Hungarian nation ", who was the head of all Bogomils and even sent his vicar to Toulouse. At the time, the dualist heresy was quite widespread under various names (Patarines, Cathari, etc), in Western Europe as well. It had taken particulary firm roots in Southern France (Toulouse) and in Lombard cities of Northen Italy. In some parts of Italy the followers of the dualist heresy were called Sclavini, which indicates their ties with Dalmatian and Bosnian Bogomils.
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