The serpent or dragon eating its own tail has survived from antiquity and can be traced back to Ancient Egypt, circa 1600 B.C.E. It is contained in the Egyptian Book of the Netherworld. The Ouroboros was popular after the Amarna period.
In the Book of the Dead, which was still current in the Graeco-Roman period, the self-begetting sun god Atum is said to have ascended from chaos-waters with the appearance of a snake, the animal renewing itself every morning, and the deceased wishes to turn into the shape of the snake Sato ("son of the earth"), the embodiment of Atum.
The famous Ouroboros drawing from the early alchemical text The Chrysopoeia of Cleopatra dating to 2nd century Alexandria encloses the words hen to pan, "one is the all". Its black and white halves represent the Gnostic duality of existence. As such, the Ouroboros could be interpreted as the Western equivalent of the Taoist Yin-Yang symbol. The Chrysopoeia Ouroboros of Cleopatra is one of the oldest images of the Ouroboros to be linked with the legendary opus of the Alchemists, the Philosopher's Stone.