A heresy is a belief or doctrine that is considered to be false or erroneous by one or more Christian denominations, i.e. what is believed to be contrary to the teaching of Christianity.
Heresies have been a major source of division and conflict within Christendom throughout its history.
Christian churches have responded to heresies in a variety of ways, including through theological debate, excommunication, and even violence.
[1] This is a list of some of the Christian heresies that have been condemned by one or more Christian Churches.