he caduceus (atin: cādūceus, from Greek: "herald's wand, or staff")is the staff carried by Hermes in Greek mythology and consequently by Hermes Trismegistus in Greco-Egyptian mythology. The same staff was also borne by heralds in general, for example by Iris, the messenger of Hera. It is a short staff entwined by two serpents, sometimes surmounted by wings. In Roman iconography, it was often depicted being carried in the left hand of Mercury, the messenger of the gods. Some accounts suggest that the oldest known imagery of the caduceus has its roots in a Mesopotamian origin with the Sumerian god Ningishzida; whose symbol, a staff with two snakes intertwined around it, dates back to 4000 BC to 3000 BC.