Several crusades were called against Bosnia, a country long deemed infested with heresy by both the rest of Catholic Europe and its Eastern Orthodox neighbours. The first crusade was averted in April 1203, when Bosnians under Ban Kulin promised to practice Christianity according to the Roman Catholic rite and recognized the spiritual supremacy of the pope. Kulin also reaffirmed the secular supremacy of the kings of Hungary over Bosnia. In effect, however, the independence of both the Bosnian Church and Banate of Bosnia continued to grow. At the height of the Albigensian Crusade against French Cathars in the 1220s, a rumour broke out that a "Cathar antipope", called Nicetas, was residing in Bosnia. It has never been clear whether Nicetas existed, but the neighbouring Hungarians took advantage of the spreading rumour to reclaim suzerainty over Bosnia, which had been growing increasingly independent. Bosnians were accused of being sympathetic to Bogomilism, a Christian sect closely related to Catharism and likewise dualist. In 1221, the concern finally prompted Pope Honorius III to preach a crusade against the Bosnian heretics. He repeated this in 1225, but internal problems prevented the Hungarians from answering his call. 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 sacraments. He was duly deposed in 1233 and replaced with a German Dominican prelate, John of Wildeshausen, the first non-Bosnian Bishop of Bosnia. The same year, Ban Matthew Ninoslav abandoned an unspecified heresy, but this did not satisfy Gregory.
Question: Who was Pope Honorius III's replacement?
Answer: Pope Gregory IX