In 1203, Pope Innocent III, with the aid of the King of Hungary, forced an agreement of Kulin to acknowledge Papal authority and religion: in practice this was ignored. On the death of Kulin in 1216 a mission was sent to convert Bosnia to Rome but failed. In 1234, the Catholic Bishop of Bosnia was removed by Pope Gregory IX for allowing heretical practices. In addition, Gregory called on the Hungarian king to crusade against the heretics. However, Bosnian nobles were able to expel the Hungarians.