The caduceus (☤; pron.: // or //; from Greek κηρύκειον kērukeion "herald's staff" ) is the staff carried by Hermes in Greek 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, guide of the dead and protector of merchants, shepherds, gamblers, liars, and thieves.
As a symbolic object it represents Hermes (or the Roman Mercury), and by extension trades, occupations or undertakings associated with the god. In later Antiquity the caduceus provided the basis for the astrological symbol representing the planet Mercury. Thus, through its use in astrology and alchemy, it has come to denote the elemental metal of the same name.
By extension of its association with Mercury and Hermes, 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).
The caduceus is often mistakenly used as a symbol of medicine and medical practice (especially in North America), due to historical confusion with the traditional medical symbol, the rod of Asclepius. The Rod of Asclepius has only a single snake and no wings, so is similar in form to the caduceus with its two snakes and often with wings.
Origin and comparative mythology 
The term kerukeion denoted any herald's staff, not necessarily associated with Hermes in particular.
Lewis Richard Farnell (1909) in his study of the cult of Hermes assumed that the two snakes had simply developed out of ornaments of the shepherd's crook used by heralds as their staff. This view has been rejected by later authors pointing to parallel iconography in the Ancient Near East. It has been argued that the staff or wand entwined by two snakes was itself representing a god in the pre-anthropomorphic era. Like the herm or priapus, it would thus be a predecessor of the anthropomorphic Hermes of the classical era.
Ancient Near East 
William Hayes Ward (1910) discovered that symbols similar to the classical caduceus sometimes appeared on Mesopotamian cylinder seals. He suggested the symbol originated some time between 3000 and 4000 BCE, and that it might have been the source of the Greek caduceus. A.L. Frothingham incorporated Dr. Ward's research into his own work, published in 1916, in which he suggested that the prototype of Hermes was an "Oriental deity of Babylonian extraction" represented in his earliest form as a snake god. From this perspective, the caduceus was originally representative of Hermes himself, in his early form as the Underworld god Ningishzida, "messenger" of the "Earth Mother". The caduceus is mentioned in passing by Walter Burkert as "really the image of copulating snakes taken over from Ancient Near Eastern tradition".
Classical antiquity 
The Homeric hymn to Hermes relates how Hermes offered his lyre fashioned from a tortoise shell as compensation for the cattle he stole from his half brother Apollo. Apollo in return gave Hermes the caduceus as a gesture of friendship. The association with the serpent thus connects Hermes to Apollo, as later the serpent was associated with Asclepius, the "son of Apollo". The association of Apollo with the serpent 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. This staff later came into the possession of the god Hermes, along with its transformative powers.
Another myth suggests that Hermes (or Mercury) saw two serpents entwined in mortal combat. Separating them with his wand he brought about peace between them, and as a result the wand with two serpents came to be seen as a sign of peace.
In Rome, Livy refers to the caduceator who negotiated peace arrangements under the diplomatic protection of the caduceus he carried.
In some vase paintings ancient depictions of the Greek kerukeion are somewhat different from the commonly seen modern representation. These representations feature the two snakes atop the staff (or rod), crossed to create a circle with the heads of the snakes resembling horns. This old graphic form, with an additional crossbar to the staff, seems to have provided the basis for the graphical sign of Mercury (☿) used in Greek astrology from Late Antiquity.
Modern use 
Caduceus is encoded in Unicode at code point U+2624: ☤.
Symbol of commerce 
A simplified variant of the caduceus is to be found in dictionaries, indicating a “commercial term” entirely in keeping with the association of Hermes with commerce. In this form the staff is often depicted with two winglets attached and the snakes are omitted (or reduced to a small ring in the middle). The Customs Service of the former German Democratic Republic employed the caduceus, bringing its implied associations with thresholds, translators, and commerce, in the service medals they issued their staff.
Misuse as symbol of medicine 
It is relatively common, especially in the United States, to find the caduceus, with its two snakes and wings, used as a symbol of medicine instead of the correct Rod of Asclepius, with only a single snake. This usage is erroneous, popularised largely as a result of the adoption of the caduceus as its insignia by the U.S. Army Medical Corps in 1902 at the insistence of a single officer (though there are conflicting claims as to whether this was Capt. Frederick P. Reynolds or Col. John R. van Hoff).
The rod of Asclepius is the dominant symbol for professional healthcare associations in the United States. One survey found that 62% of professional healthcare associations used the rod of Asclepius as their symbol. The same survey found that 76% of commercial healthcare organizations used the Caduceus symbol. The author of the study suggests the difference exists because professional associations are more likely to have a real understanding of the two symbols, whereas commercial organizations are more likely to be concerned with the visual impact a symbol will have in selling their products.
The initial errors leading to its adoption and the continuing confusion it generates are well known to medical historians. The long-standing and abundantly attested historical associations of the caduceus with commerce, theft, deception, and death are considered by many to be inappropriate in a symbol used by those engaged in the healing arts. This has occasioned significant criticism of the use of the caduceus in a medical context.
|“||As god of the high-road and the market-place Hermes was perhaps above all else the patron of commerce and the fat purse: as a corollary, he was the special protector of the traveling salesman. As spokesman for the gods, he not only brought peace on earth (occasionally even the peace of death), but his silver-tongued eloquence could always make the worse appear the better cause. From this latter point of view, would not his symbol be suitable for certain Congressmen, all medical quacks, book agents and purveyors of vacuum cleaners, rather than for the straight-thinking, straight-speaking therapeutist? As conductor of the dead to their subterranean abode, his emblem would seem more appropriate on a hearse than on a physician's car.||”|
—Stuart L. Tyson, "The Caduceus", in The Scientific Monthly
See also 
- Aaron's rod
- Bowl of Hygieia
- Rod of Asclepius
- Serpent (symbolism)
- Mithraic mysteries
- It is unclear whether the inscription refers to a patron/donor or a sculptor
- The Latin word cādūceus is an adaptation of the Greek κηρύκειον kērukeion, meaning "herald's wand (or staff)", deriving from κῆρυξ kērux, meaning "messenger, herald, envoy". Liddell and Scott, Greek-English Lexicon; Stuart L. Tyson, "The Caduceus", The Scientific Monthly, 34.6, (1932:492-98) p. 493
- Hornblower, Spawforth, The Oxford Classical Dictionary, 3rd Ed., Oxford, 1996, pp 690-691
- e.g. the Unicode standard, where the "staff of Hermes" signifies "a commercial term or commerce"; see also: Walter J. Friedlander, The Golden Wand of Medicine: A History of the Caduceus Symbol in Medicine, Greenwood, 1992, p83
- As one specialized study of symbolism notes, "In modern times the caduceus figures as a symbol of commerce, since Mercury is the god of commerce. M. Oldfield Howey, The Encircled Serpent: A Study of Serpent Symbolism in All Countries And Ages, New York, 1955, p77
- "The name of the god Mercury cannot be disassociated from the word merx, which means merchandise. Such was the sentiment of the ancients" Yves Bonnefoy (Ed.), Wendy Doniger (Trans.), Roman and European Mythologies, University of Chicago Press, 1992, p135; "Mercury was the Roman name for the Greek god Hermes. His Latin name was apparently derived from merx or mercator, a merchant." Michael E. Bakich, The Cambridge Planetary Handbook, Cambridge University Press, 2000, p85; Latin merx is the root of the English words Commerce, Market, Mart, Mercantile, Mercenary, Mercer, Merchant and Mercury, as can be seen by referring to any dictionary including etymological information.
- Oxford Classical Dictionary, 3rd edition, Ed. Hornblower and Spawforth, s.v. "Hermes".
- Farnell, The Cults of the Greek States, Vol. V, p. 20, cited in Tyson 1932:494
- A. L. Frothingham, Babylonian Origin of Hermes the Snake-God, and of the Caduceus I American Journal of Archaeology Vol. 20, No. 2 (Apr. - Jun., 1916), pp. 175-211 http://www.jstor.org/stable/497115 Frothingham characterizes Farnell's simplistic view of the origin of the symbol as a "frivolous and futile theory".
- William Hayes Ward, The Seal Cylinders of Western Asia, Washington, 1910
- A.L. Frothingham, "Babylonian Origins of Hermes the Snake-God, and of the Caduceus", in American Journal of Archaeology, Vol. 20, No. 2, pp.175-211
- Burkert, Greek Religion 1985: II.2.8, p.158; Burkert notes H. Frankfort, in Iraq, 1 (1934:10) and E.D. van Buren, in Archiv für Orientforschung, 10 (1935/36:53-65.
- Tyson 1932:494.
- Deldon Anne McNeely Mercury rising: women, evil, and the trickster gods, Spring Publications, 1996, ISBN 978-0-88214-366-8, p. 90. "Homer tell us that Hermes' caduceus, the golden wand, was acquired by Hermes from Apollo in exchange for the tortoise-lyre; later the caduceus changed hands again from Hermes to Apollo's son, Asclepius."
- S. Davis, 'Argeiphontes in Homer—The Dragon-Slayer', Greece & Rome, Vol. 22, No. 64 (Feb., 1953), pp. 33-38, http://www.jstor.org/stable/640827 citing W. H. Roscher, Omphalos (1913).
- Blayney, Keith (September 2002). "The Caduceus vs the Staff of Asclepius". Retrieved 2007-06-15.
- Tyson 1932:495
- "Signs and Symbols Used In Writing and Printing", p 269, in Webster's New Twentieth Century Dictionary of the English Language, unabridged, New York, 1953. Here the symbol of the planet Mercury is indicated as "the caduceus of Mercury, or his head and winged cap".
- For example, see the Unicode standard, where the "staff of Hermes" signifies "a commercial term or commerce".
- F.H. Garrison, "The Use of the Caduceus in the Insignia of the Army Medical Officer", in Bull. Med. Lib. Assoc. IX (1919-20), 13-16
- Engle, Bernice (Dec 1929). "The Use of Mercury's Caduceus as a Medical Emblem"". The Classical Journal 25 (1): 205.
- Friedlander, Walter J (1992). The Golden Wand of Medicine: A History of the Caduceus symbol in medicine. Greenwood Press. ISBN 0-313-28023-1.
- An allusion to John Milton's description of Belial in Paradise Lost II.113-114.
- Tyson, Stuart L (1932). "The Caduceus". Scientific Monthly 34 (6): 495.
Further reading 
- Walter J. Friedlander, The Golden Wand of Medicine: A History of the Caduceus Symbol in Medicine, 1992. ISBN 0-313-28023-1; ISBN 978-0-313-28023-8.
- Bunn, J. T. Origin of the caduceus motif, JAMA, 1967. United States National Institutes of Health: National Center for Biotechnology Information. PMID 4863068
- Burkert, Walter, Structure and History in Greek Mythology and Ritual, Translation, University of California, 1979.
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