There's actually proof linking back straight to Imhotep, so basically Hypnosis has roots older than 5000 years in the past. But who is this Imhotep guy? Well, Imhotep is the builder of the pyramids. He was actually a priest and had the reputation of a magician. Perceived to be the go to guy in regards to science and magic (they were intertwined back then) the pharaoh gave Imhotep the task of building the greatest pyramids in the world, and so he did. Imhotep knew his stuff. Can't argue with that, the guy had some leadership and knowledge in that elongated skull of his!
Hypnosis and the Pyramids
Egyptians used healing sanctuaries to heal people, mental illnesses, what we would class today as psychological problems. Those healing places were called "Sleep Temples." Imhotep owned multiple such sleep temples, in which he performed hypnosis. They didn't call it that back then, but nevertheless, that's what is was. You see, the subconscious mind has always existed, even though we only discovered it recently and some will have you believe that it doesn't exist. In these temples, the sick person was induces into a sleep like trance; priests then tried to make sense of the person's dreams in order to find out more about the illnesses and to find a potential cure for it.
Must of be a heck of a sight to see "patients" coming into these temples, these catacombs, and being introduced to, what was perceived back then, magic. That's what the normal folks thought of hypnosis, that's why only priests and priestesses knew the secrets.
These hypnosis secrets were handed down and taught only to the selected disciples, which had to go through years of apprenticeship to become practitioners, or priests as it were. Then these selected few could attend and help the main priest with the induction.
Egyptians relied heavily on scents and perfumes for their induction techniques. They would do these hypnotic inductions in isolated rooms, with no windows, so the scents didn't escape the room and the "patient" had to sniff up everything.
Once the person was ready, usually 3-5 minutes, the chanting and humming would begin, creating a religious feeling inside the chamber, which mixed with the scent and the figure of authority (the priest) would cause the subject to fall into a deep trance. With their eyes closed, people would then listen to the voice of the priest and follow his instructions, which usually were commands to narrate the dreams that particular person had.