Heresy in the Catholic Church denotes the formal denial or doubt of a core doctrine of the Roman Catholic Church. Heresy has a very specific meaning in the Catholic Church and there are four elements which constitute formal heresy; a valid Christian baptism; a profession of still being a Christian; outright denial or positive doubt regarding a truth that the Catholic Church regards as revealed by God; and lastly, the disbelief must be morally culpable, that is, there must be a refusal to accept what is known to be a doctrinal imperative. Therefore, to become a heretic in the strict canonical sense and be excommunicated, one must deny or question a truth that is taught as the word of God, and at the same time recognize one's obligation to believe it. If the person is believed to have acted in good faith, as one might out of ignorance, then the heresy is only material and implies neither guilt nor sin against faith.
During its early centuries, the Christian church dealt with many heresies. ... In the 12th and 13th centuries, however, the Inquisition was established by the church to combat heresy; heretics who refused to recant after being tried by the church were handed over to the civil authorities for punishment, usually execution
