Bosnian Crusade

The first crusade was averted in April 1203, when the Bosnians under Ban Kulin promised to practice Christianity according to the Roman Catholic rite and recognized the spiritual supremacy of the Pope.

It has never been clear whether Nicetas existed, but neighbouring Hungary took advantage of the rumour to reclaim suzerainty over Bosnia, which had been growing increasingly independent.

[1] Honorius III's successor, Pope Gregory IX, accused the Catholic bishop of Bosnia himself of sheltering heretics, in addition to illiteracy, simony, ignorance of the baptismal formula and failure to celebrate Mass and the sacraments.

It is possible that the Bosnians had failed to align their church with Rome, but the crusade actually served as a perfect excuse for the Hungarians to expand their authority.

[1] Gregory promised indulgences to prospective crusaders and entrusted Coloman, the younger son of Andrew II and brother of Béla IV, with executing the military action.

The delay may have been caused by the popular resistance in the north of the country, Soli, where the mountainous terrain helped "many heretics" fight the crusaders.

[1][4] In August 1236, Pope Gregory ordered the crusaders not to pester Matthew Ninoslav's relative Sibislav, the knez of Usora, or his mother, who were both "good Catholics" among heretical nobles, "lilies among thorns".

The crusaders failed to conquer all of Bosnia, however, as Matthew Ninoslav continued to act as ban throughout the conflict in the central parts of his realm, where Dominicans never set foot.

[1] Bosnia retook the occupied territories and maintained its level of independence following what turned out to be a Hungarian war of conquest that was sanctioned as a crusade.

[1] King Charles Robert once declared that any Hungarian who attacked Bosnia, ruled by his friend Stephen II, would be regarded as a traitor.