The use of hypnosis can be dated as far back as ancient Egyptian times. There is evidence on a bas-relief in a temple at Thebes of a soothsayer inducing trance on a subject by means of revolving a pebble upon the chest of the victim whilst chanting. Shamans, better known as witch doctors, medicine men or healers, would mentally prepare themselves in order to heighten their awareness and concentration. They did this by placing themselves in a darkened quiet room, or an isolated place away from all other distractions. They would visualize images of going down into the earth whilst listening to rhythmic, repetitive chanting and drum beats. By focusing inwardly and concentrating on the monotonous sounds they were able to achieve the trance state.