Doctor David Waxman wrote:

"From the beginnings of the human race, man has endeavored to impose his will and strength upon his fellow for good or for evil.  From the dawn of history, with the use of witchcraft or of wizardry, of revelation through supernatural agencies, with the power of the word or the use of suggestion, he has sought to influence the destiny of others.  From the accidental discovery of a natural phenomenon, through magical powers and magnetic fluids have emerged the refined techniques of the twentieth century, which produce the state known as hypnosis."

The earliest written records can be found in texts like the Ebers Papyrus; an Egyptian medical text dating around 1550BC. The Ebers papyrus is written in hieratic script and preserves for us the most voluminous record of ancient Egyptian medicine known. The 110-page scroll contains some 700 magical formulas and remedies. Although it contains many incantations meant to turn away disease-causing demons and other superstition, there is also evidence of a long tradition of empirical practice and observation.

Hypnosis has been around for many years.  The Ancient Egyptians had their Temples of Sleep and the Greeks their Shrines of Healing. Some of the hieroglyphics found on tombs date their knowledge back as early as 3000 B.C. 

Sleep temples were hospitals of sorts, healing a variety of ailments, perhaps many of them psychological in nature. Treatment involved chanting, placing the patient into a trancelike or hypnotic state, and analyzing their dreams in order to determine treatment. In Greece, they were built in honor of Asclepius, the Greek God of Medicine. 

Some other cultures that understood the power of hypnosis were the Persian Magi, Celtic Druids, Chinese teachers of religion, Hindu Fakirs and African Witch Doctors. Perhaps it even goes back to prehistoric times, handed down by various rituals.

YPNOS (The Greek God of  Sleeping )

Ceremonies and mysticism were used to provide even more reason for the participants to believe in the temples or healers ability to heal. You could also ascribe to hypnosis the many healings and miracles of relics, holy men and shrines.  According to a Greek legend the  gods were looking for a place to hide the greatest power that they held. They thought about placing it on the highest mountain top but they figure we would look there eventually. This discussion went on with different gods suggesting different places but none of them would be safe from humans looking. Eventually it was YPNOS that suggested that the greatest gift be hidden in each of us because we would never think to look inside ourselves for it.

Hippocrates (460-377 BC) Greek Physician

 
He maintained that the brain not only controlled the entire body, but also our feelings and emotions, as well as being the seat of disease. The Hippocratic oath named after Hippocrates was created long after his death.