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.
Serpent (symbolism) Heracles for one of his Twelve Labors. The constellation Serpens represents a snake being tamed by Ophiuchus the snake-handler, another constellation. The most probable interpretation is that Ophiuchus represents the healer Asclepius. Occasionally, serpents and dragons are used interchangeably, having similar symbolic functions. The venom of the serpent is thought to have a fiery quality similar to a fire spitting dragon. The Greek Ladon and the Norse Níðhöggr (Nidhogg Nagar) are sometimes described as serpents and sometimes as dragons. In Germanic mythology, "serpent" (Old English: "wyrm", Old High German: "wurm", Old Norse: "ormr") is used interchangeably with the Greek borrowing