The Bosnian Church broke from the Catholic Church in the thirteenth century, making it the fist protestant church in Europe. There are no sources today that describe the theology of this Medieval Gnostic church that were written by anyone actually connected with the Bosnian Church – all that is known was written by heresiologists.

The Bosnian Church likely organized itself after its Roman Catholic counterpart. The Bosnian Church consisted of clergy called Christians (Krstjani) that lived together in monasteries. The leading title of the organization was the Bishop, or the djed (grandfather). The head of the monastery was the gost (guest). The monasteries consisted of the djed and his council of twelve gosts. The Bosnian Church did not spread their monasteries throughout Bosnia; rather, the Church centered them within the country.

Characteristically, the Bosnian Church retained some teachings from the Catholic Church, but developed its own teachings; many strongly opposed to those of the Orthodox Church. The Bosnian Church denied the trinity and the cross as a symbol of faith. Further, the Bosnian Church believed that Christ’s incarnation is an illusion, and his physical death on the cross could not have actually happened. The Bosnian Church also taught that Satan’s powers were almost equal to God’s – a trait likely derived from their Manichaean counterparts. The Bosnian Church also rejected mass and baptism. Ultimately, the Bosnian Church rejected wealthy monasteries (probably the cause of their own unique organization) and traditional church buildings.