One of the earliest known Ouroboros motifs is found in the Enigmatic Book of the Netherworld, an ancient Egyptian funerary text found in the tomb of pharaoh Tutankhamun dating back to the 14th century BC. The text concerns the actions of the god Ra and his union with the god Osiris in the underworld. The Ouroboros is depicted twice on the figure: holding their tails in their mouths, one encircling the head and upper chest, the other surrounding the feet of a large figure, which may represent the unified Ra-Osiris (Osiris born again as Ra). The Ouroboros also appears elsewhere in Egyptian sources, where, like many Egyptian serpent deities, it represents the formless disorder that surrounds the orderly world and is involved in the world’s periodic renewal. The symbol persisted in Egypt through to Roman times when it frequently appeared on magical talismans, sometimes in combination with other magical emblems.
Later, in Gnosticism (a collection of religious ideas and systems which coalesced in the late 1st century AD among Jewish and early Christian sects), the serpent biting its tail was used to symbolise eternity and the soul of the world. The famous Ouroboros drawing from the early alchemical text The Chrysopoeia of Cleopa- tra probably originally dating back to the 3rd century, Alexandria, encloses the words hen to pan, “the all is one”. Its black and white halves may perhaps represent a Gnostic duality of existence, analogous to the Taoist yin and yang symbol. The chrysopoeia Ouroboros 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. Another early example of an Ouroboros (as a purely artistic representation) was discovered in China, on a piece of pottery in the Yellow River basin. The jar belonged to the neolithic Yangshao culture which occupied the area along the basin from 5000–3000BC.
In modern civilisations, the Ouroboros is often interpreted as a symbol of eternal cyclic renewal or the cycle of life, death and rebirth; the snake’s skin-sloughing symbolises the transmigration of souls. The snake biting its own tail is a fertility symbol in some religions: the tail is a phallic symbol and the mouth is a yonic or womb-like symbol. It also appears in mythology worldwide and is used as a symbol in chemistry, cosmology, cybernetics and psychology, for example, Swiss psychiatrist Carl Jung saw the Ouroboros as an archetype and the basic mandala of alchemy.