Caduceus is a continuation of the older Indo-European dragon-slayer motif. Wilhelm Heinrich Roscher (1913) pointed out that the serpent as an attribute of both Hermes and Asclepius is a variant of the "pre-historic semi-chthonic serpent hero known at Delphi as Python", who in classical mythology is slain by Apollo. One Greek myth of origin of the caduceus is part of the story of Tiresias, who found two snakes copulating and killed the female with his staff. Tiresias was immediately turned into a woman, and so remained until he was able to repeat the act with the male snake seven years later.
Snake worship Parthenon. Asclepius, the son of Apollo and Koronis, learned the secrets of keeping death at bay after observing one serpent bringing another (which Asclepius himself had fatally wounded) healing herbs. To prevent the entire human race from becoming immortal under Asclepius's care, Zeus killed him with a bolt of lightning. Asclepius' death at the hands of Zeus illustrates man's inability to challenge the natural order that separates mortal men from the gods. In honor of Asclepius, snakes were often used in healing rituals. Non-poisonous Aesculapian snakes were left to crawl on the floor in dormitories where the sick and injured