In Christianity, an exorcism is an act of expelling demons from a possessed person. It typically involves prayers for deliverance, and the exorcist may employ holy objects and sacramentals such as the cross, holy water, incense and so on. In Roman Catholic Church, a priest needs an express permission by his bishop to exorcize; in other Churches, exorcisms may be performed by any priest/minister, or even any layman. An exorcism is an essential part of Catholic and Orthodox baptisms.