The teachings of the Bosnian Church constitute one of the greatest mysteries of the medieval period of Bosnian history. The issue whether it acted in the realms of heresy or orthodoxy has been disputed in a scientific battleground in historiographical circles many times. Just a touch less controversy is linked with the nature of military missions proclaimed and executed against Bosnian ''heretics''. Some authors characterize these conflicts as religious, so typical for crusades, while others, however, emphasize the political and territorial pretensions of Hungary regarding Bosnia, as the main motif, describing the Holy war idea as a cover story for the sake of the Papal curia. The triangle between Hungary, Rome and Bosnia was the focal point of discourse in which numerous accusations on one side and explanations from the other occurred, along with war propaganda, anti-heretic warnings and attempts to prove innocence and that right path were followed. Interestingly, the Bosnian medieval state, so many times threatened with crusades against it, became the leading advocate for crusade missions against the Ottoman danger in the 15th century. This transformation did not occur because crusader ideas prevailed, but rather because of evolution within the social and administrative structures. This work will explore all the differences between the opposing historiographic streams, their approaches regarding sources and literature. The main goal is to determine how research performed with more or less identical source material, can produce such opposing results.