The Greek symbol caduceus (two snakes wrapped around a winged staff) is commonly associated with the messenger of the gods. In Roman iconography the caduceus was often depicted being carried in the left hand of Mercury, guide of the dead and protector of merchants, shepherds, gamblers, liars, and thieves. The caduceus is also a recognized symbol of commerce and negotiation, two realms in which balanced exchange and reciprocity are recognized as ideals. This association is ancient, and consistent from the Classical period to modern times. The caduceus is also used as a symbol representing printing, again by extension of the attributes of Mercury (in this case associated with writing and eloquence).
