Achemy and Gnosticism[edit]

Early alchemical ouroboros illustration with the words ἓν τὸ πᾶν ("The All is One") from the work of Cleopatra the Alchemist (c. third century, Egypt).
The famous ouroboros drawing from the early alchemical text The Chrysopoeia of Cleopatra (Ἡ χρυσοποιία τῆς Κλεοπάτρας) probably dating to third century Alexandria encloses the words hen to pan (ἓν τὸ πᾶν), "the all is one". Its black and white halves represent the Gnostic duality of existence, leading some to see it as an analog of the Taoist yin and yang symbol. The chrysopoeiaouroboros of Cleopatra the Alchemist is one of the oldest images of the ouroboros to be linked with the legendary opus of the alchemists, the philosopher's stone.
As a symbol of the eternal unity of all things, the cycle of birth and death from which the alchemist sought release and liberation, it was familiar to the alchemist and physician Sir Thomas Browne. In his A Letter to a Friend, a medical treatise full of case-histories and witty speculations upon the human condition, he wrote of it:
... that the first day should make the last, that the Tail of the Snake should return into its Mouth precisely at that time, and they should wind up upon the day of their Nativity, is indeed a remarkable Coincidence, ...
In Gnosticism, a serpent biting its tail symbolized eternity and the soul of the world. The Gnostic Pistis Sophia (c. 400 AD) describes the ouroboros as a twelve-part dragon surrounding the world with his tail in his mouth.[12]