“Demons were always ready to enter the bodies of humans and domesticated animals where, attracted by the warmth and moisture, they could dwell, like parasites, for long years. In doing so they caused various diseases and a derangement of the senses. Not all diseases, of course, were due to demons, and some would respond to medical treatment or curative waters; yet a great many were the result of possession and lay, therefore, beyond the physician’s competence. Only an exorcist could help, and his methods were rough. He would often strike the patient in the chest or throw him to the ground and step upon his neck. The demon, always unwilling to depart, could cause levitation; when forced out, he convulsed the patient, made him tear his clothes, and then left him unconscious. But the cure, once effected, was complete.” – Cyril Mango, Byzantium: The Empire of New Rome