Dragon and Serpent cults in the Graeco-Roman world.

Summary: Among the ancients there were popular drakon cults, running parallel to - for example - Mithraic mysteries; Marcus Aurelius was an initiate as Pater Noster in Mithraism and a Drakon. The ophis-worship had a much older provenance, as it was known among the Hindis, Egyptians, and throughout the Orient. The caduceus rod with wings originated from this cult and it was signifying healing (spagyric medicine: venom used in right amounts could heal certain maladies). The great Aesculap was considered a Drakon, while Drakon-Aion was another name for the Solar Aion, in Chaldean mysteries the transcendent Sun.

It is of interest that the cults were suppressed by Christianity, upon unsuccessful attempt to symbolically 'marry' Christ to Artemis-Drakaina and legitimize his rule among Roman citizenry - for a 'god' without a wife was quite worthless. That of course was not the main reason for cult suppression. The symbolic attempts to marry Christ to 'Artemis-Drakaina' did not work and her temples were destroyed (St. John of Apocalypse was known as the prime destroyer of her temples). Drakon cults were -in majority - staffed by females. The origin of the 'Book of the Revelation' was based in hatred for Snake and Dragon cults, and the 'Great Whore' was no else than Artemis, she was the Patroness of Dragons (Orphic Mysteries).
For further information, read:
Ogden, Daniel. 2013. Drakon dragon myth and serpent cult in the Greek and Roman worlds. Oxford: Oxford University Press
Aronen, Jaakko. "Dragon Cults and νύμφη δράκαινα in IGUR 974." Zeitschrift Für Papyrologie Und Epigraphik 111 (1996): 125-32. http://www.jstor.org/stable/20189729.