Imhotep was a physician, architect, and priest, and a prominent figure in ancient Egypt. The ancient Egyptians revered Imhotep and dedicated a sleep temple to him. Sleep temples were also known as dream or incubation temples. There, people slept to seek divine intervention or healing through dreams, particularly in ancient Egypt and Greece. Patients underwent rituals, fasting, and prayers to prepare their bodies and minds. Within the temple, they slept in designated areas, and priests chanted and performed ceremonies to invoke the gods. The Egyptians believed that the gods appeared during sleep and offered solutions, either through symbolic dreams or direct healing.

Paracelsus was a Swiss physician, alchemist, theologian, and philosopher of the Renaissance. He was a pioneer in several aspects of the Renaissance "medical revolution" and emphasized the value of observation combined with traditional knowledge. Paracelsus was one of the first physicians to suggest that mental well-being and moral conscience have a direct influence on physical health. He proposed that a person's mental state could either cure or cause illness. According to his theory, a person could remain healthy through sheer willpower. Regarding mental illness, Paracelsus emphasized the importance of sleep and sedation, believing that sedation could cure mental disorders.

Franz Anton Mesmer, a Viennese physician, began to investigate an effect he called "animal magnetism" or "mesmerism." The word "animal" is related to the adjective "animal" and referred to both animals and humans. In 1774, Mesmer created an "artificial flood" in a hysterical patient by having her swallow an iron-containing preparation and then applying magnets to various parts of her body. She reported feeling currents of a mysterious fluid flowing through her body and was free of her symptoms for several hours. Mesmer did not believe that the magnets alone had caused the cure. He believed that he had transferred the animal magnetism he had accumulated through his work to her. Soon he stopped using magnets as part of his treatment. He claimed that the effects were due to an invisible force called "animal magnetism," and that his subjects had developed paranormal abilities such as telepathy. Many patients experienced strange sensations or suffered from cramps, which were interpreted as crises intended to bring about healing. Mesmer often ended his treatments by playing a glass harmonica. His clients were evidently "hypnotized" (mesmerized) by his treatments, and the word still refers to his name today.

Marquis de Puységur was a French magnetizer and aristocrat from one of the most illustrious families of the French nobility. A student of Mesmer, he was the first to describe and coin the term somnambulism, meaning sleepwalking. One of his first and most important patients was a 23-year-old peasant in the service of the Puységur family. The young man was easily "magnetized" by Puységur but exhibited a strange form of sleep trance, never before observed in the early history of mesmerism. Puységur noted the similarity of this sleep trance to natural sleepwalking or somnambulism and called it "artificial somnambulism." Today, we know similar states as "hypnosis," although this term was coined much later, in 1842, by James Braid. Marquis de Puységur is considered today to be one of the pre-scientific founders of hypnosis, which developed from animal magnetism or mesmerism.

James Braid was a Scottish surgeon, natural philosopher, and gentleman scientist, as well as a significant pioneer of hypnosis and hypnotherapy, and an important and influential forerunner of both hypnotic and chemical anesthesia. Braid used the term "hypnosis," specifically referring to the subject's state rather than the techniques employed by the practitioner, to distinguish his own unique, subject-centered approach from that of the mesmerist surgeons who preceded him. James Braid coined the term "hypnosis" as an abbreviation of "neurohypnosis," meaning "sleep of the nerves." Braid strongly opposed the mesmerists' views, particularly their claim that their effects were due to an invisible force called "animal magnetism" and their assertion that their subjects developed paranormal powers. Instead, Braid maintained a skeptical stance and sought to explain mesmeric phenomena using established laws of psychology and physiology. Braid is regarded by many as the first true "hypnotist", in contrast to the mesmerists and other magnetists before him.

Ambroise-Auguste Liébeault was the founder of the Nancy School. He was the first to write about the necessity of cooperation between hypnotist and participant, calling it rapport. Rapport describes a close and harmonious relationship in which the individuals or groups involved are "in tune," understand each other's feelings or ideas, and communicate smoothly.