The expulsion of an evil spirit by a command, ritual or prayer is called exorcism. At the root of exorcism lies belief in the power to transfer a spiritual being from place to place by ritual acts and words.

Exorcism may have originated from old rituals of propitiation dating back from the Hittites of Asia Minor who transmitted to the early romans. The romans before the final assault against a hostile town carried out the evocation. It was a solemn ritual of calling the gods of the enemy. The gods were invited to join Rome with promises of worship and good treatment if they did. Josephus also mentions a method of exorcism prescribed by Solomon, which had "prevailed or succeeded greatly among them down to the present time."  Unfortunately, Josephus does not describe the method used. 

In the Old Testament, there are no stories of exorcism except the episode of Tobias and Sarah in the Apocryphia (Tobit 6-8). Sarah was not in fact possessed but guarded by a demon, much as in later stories princess were guarded by dragons.

In The prayer of Nabodinus, one of the manuscrits from the Qumarn discovery, a Jewish exorcist is credited from the forgiveness of sins and consequent healing. Another apocryphal, Testaments of the Twelve Patriarchs bears witness to it.

Josephus made the claim that God had taught Solomon the art of exorcism but the Scripture has no trace of this. By the time Christ came on earth, exorcism was well known among Jews. All the Gospels refer all the time to the many exorcism conducted by the Christ. Diabolical infection is never confused with exorcism, disease with possession even if some patients suffered from both.

Waterless places are spoken out in the Gospels (Matthew 12.43), as an unsatisfactory abode for evil spirits and it was generally believed that water was their element. As early as 150 AD, the Church began to have an exorcism for the water used for baptism.

 Even the coming of Jesus on earth can be interpreted as a giant exorcism on a planet Earth controlled by the Demon. Jesus fooled Satan as he exchanged his life against the world but eventually resuscitated and went back to Heaven. 

The practice grew of treating all mental and epileptics as if they were possessed by the Devil. A part of the Church was set aside for those who came within this broad category and exorcists were appointed to stay with these sufferers during the service and keep them quiet.

In 251, Pope Cornelius had a total of 52 men as exorcists, readers and doorkeepers. Having preceded baptism, exorcism became to be integrated to it.

The whole world was considered in the power of the Devil and demons were even supposed to live inside the bodies of newborn children. A voluntary renunciation was required of the candidate, because the human will was a key element in the possession, no one could be maneuvered by the Devil unless he had given his consent.  When infants were baptized, sponsors on their behalf undertook the renunciation.

 Exorciso te immunde spiritus

Exib ab

In early Christian times every Christian could exorcize but later the Church created a special Order. The ritual has been enriched and amended several times. Leon X imposed the method created by Alberto Castellani in 1523 in his Liber sacerdotalis. In 1614, Paul V created the Roman Ritual that is slightly revised in 1926 and 1952 and still in use.

Human suggestion, by hypnosis or even by telepathy, can go to work upon bodily flaw and weakness and cure the “possessed» by removing the psychosomatic affection.