Exorcism is the ritual act of expelling demons or evil spirits from a person or any other creature. In former times, sickness was believed to have been caused by these spirits. Possession had been believed to occur and exorcism has varied according to the level of possession. Blessings would be done to remove the person from the power of evil. In this way, exorcism was a kind of prayer for healing, since evil and sins are considered types of sickness and disharmony. When a person is possessed, thier personality is taken over by the personal presense of the devil. Voluntary and involuntary possession have been claimed. Exorcism is practiced in many religions in the world. The New Testament records many instances of exorcisms being performed by Jesus. In one of the most dramatic of thesae, he expelled "a legion" of unclean spirits from a possessed man, which then entered into a herd of swine and drove them into the sea.