Hermes Trismegistus is the mythical author of a series of texts grouped together under the name of Corpus Hermeticum and represents one of the bases in astral magic. Hermes's texts are full of Gnostic undertones and inseparable from its magic dimension. They reveal the way for initiates to make their ascension towards the divine. This journey through the heavenly bodies requires passwords and magic signs to remove the negative matter and release the positive spirit. That is why Hermes talks of the benefits of such invocations and discloses the mysterious keys in sympathetic and talismanic magic.

Although Asclepius is presented as a description of magic practices, the texts of particular interest to us here are the Liber Hermetis Trimegisti, which deals with astrological magic, and especially the Liber Sacer, which reveals the secret of astrological medicine and the recipes for healing all ailments.

The hermetic magic that inspired the philosophers of the Renaissance is based on the following principle: it involves capturing the power of a planet using the plants, animals, stones and metals belonging to it. The image of the planet then has to be inscribed on a talisman of the appropriate stone and the invocation made on the day of the right astrological conditions.

The Liber Sacer explains this game of correspondence and influence for the purpose of invoking any sign of the zodiac, decan or star.

This is an example of the instructions given by Hermes to cure illnesses: 

Hermes to Asclepius: "each sign of the zodiac has power over its own member and produces a certain affection in that member, so that if you wish to avoid suffering what has to be suffered due to the decans, inscribe the forms and figures of the decans themselves onto the stones, and after placing the plant and form of each decan beneath the stone and making a phylactery, carry it like a powerful and blessed aid for your body "

The decans are the masters of the human body and each one is attributed a part of the body. To take action on this part, you must find the stone and plant in 'sympathy' with the appropriate decan, and then inscribe its image on the corresponding stone and place an extract of the plant on top of the stone and then bind it all in a ring, which you must then wear and avoid eating the antipathetic food of the decan.