Caduceus

One of Mercury’s or Hermes’ most iconic possessions is His wand or “herald’s staff,” a symbol which remains ubiquitous today but whose design and meaning has changed in major ways since ancient times. This article aims to breakdown its original attributes, history, and symbolism that are largely forgotten today.

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A beautifully detailed, full-color fresco of a tan, shining, muscular Mercury. He holds His caduceus and is looking over His shoulder with a serious expression. He looks more mature than the previous illustration, but is still beardless. He has brown curly hair and a red chlamys drapes behind him and over one forearm.
Fig. 1 4th style Pompeiian fresco (1st century CE).

History and uses

Properly known as a κηρύκειον (kerykeion, from Greek κῆρυξ ‘herald’), which was adapted as caduceus in Latin, the staff was not unique to Hermes. It existed as an actual physical object carried by heralds to prove their authenticity and authority to deliver messages for those in power 2 — and by extension to assure their protection while traveling sometimes hostile territory to do so.

The caduceus was also a priestly instrument. Multiple Roman frescoes (see below) show priests of Isis wielding it as the Goddess greets Io. Men known as caduceators also wielded it as part of their role in brokering peace negotiations, according to Servius, who compared them to the fetial priests responsible for war (see section “Caduceus as a Peace Sign”).

Besides priests, a number of Goddesses also carry the caduceus, such as Iris (a winged angel of Hera and the Olympians), Felicitas, and Pax. Nike or Victoria have also sometimes been said to carry it, though I cannot find an example that positively identifies Them over Iris or Pax. Additional figures in art who carry kerykeia include mortal heralds such as Talthybios (from the Trojan War).

Bronze kerykeion on museum display. It is a tall, simple rod with a terminal at the bottom. The top curves up into a circular loop and crescent shape that ends in snake heads which are staring at each other. The top part of a mottled, damaged bronze caduceus on display in a museum. It has two oval rings that are bound together with a double wrap of the bronze tubing. The staff extends up through the bottom ring. At the base of the bottom ring is a pair of small wings, almost like a hummingbird's. The tubing that forms the bottom ring coils around the staff below.
Fig. 2 Bronze kerykeion from Sicily, 5th cent. BCE.
Fig. 3. Bronze caduceus from Centum Prata (Switzerland), 1st – 2nd cent. CE.

Hermes’ association with the kerykeion is nearly absolute in visual art even from the earliest times, but the literary or mythological sources painted a murkier picture. Hermes was not initially said to have a herald’s staff, per se, and His staff, or wand, was ascribed a number of other properties.

The Iliad 1 and Odyssey 3 tell us Hermes has a golden wand (ῥάβδος, rhabdos) with the power to both lull and raise mortals from sleep, and with which He leads shades to the Underworld.

Closeup of red-figure vase art of the Goddess Iris flying forth, holding Her caduceus downards behind Her. She has large wings on Her back, wears an ornate dress and shawl, and a laurel on Her head Closeup of a damaged white-figure vase showing the mortal herald Talthybios. He raises one hand and holds His caduceus in the other. He wears a pileus, beard, a chiton wrapped around like a shawl, and boots without wings.
Fig. 4 The Goddess Iris, with kerykeion.
Fig. 5. The mortal herald Talthybios from the Trojan War, with kerykeion.

The Homeric Hymns4 recount that Apollo gave Hermes a golden wand (ῥάβδος, χρυσόρραπις, rhábdos, chrysórrhapis) in exchange for Hermes’ vow to not steal from Him again. This wand is said to have three branches (τριπέτηλος, tripételos), to keep its bearer unscathed, and to help accomplish any task that is Good. Apollodorus5 alternatively relates that Hermes traded His panpipes for the wand, and that Apollo had used this wand for herding cattle.

It’s not until around seven centuries later that we find literary myths more clearly describing the caduceus depicted in art, and explaining its invention6 — i.e., that Mercury used a “small rod” (virgula, rhabdos) to intervene in a fight between two snakes which then intertwined in union around it.

Closeup of a faded Roman fresco showing a priest of Isis holding out a sistrum in one hand and gleaming gold caduceus in the other. He wears a toga and laurel wreath, with a small metal pot hanging from his wrist.
Fig. 6 Priest of Isis, with sistrum and caduceus.

Caduceus design

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[The caduceus] shows a pair of serpents, male and female, intertwined; the middle parts of the serpents’ coils are joined together as in a knot, called the knot of Hercules; their upper parts are bent into a circle and complete the circle as they meet in a kiss; below the knot their tails rejoin the staff at the point at which it is held, and at that point appear the wings with which they are provided.

— Macrobius 7

Macrobius provides us with a succinct explanation of the canonical caduceus’ design that could hardly be improved upon, to which I would only note some stylistic variations in how it was rendered in works of art:

A small caduceus made of dark bronze with green and rust patina. Two scaly snakes with crests on their heads twist into a knotted figure-8, kissing at the top. One of their tails wriggles down the staff. A pair of large, stylistic wings spreads out beneath them. The staff is tapered.
Fig. 7 A detailed caduceus, showing the elements mentioned by Macrobius.
A glass museum case showing one full bronze kerykeion and the tops of 4 others. They each show the two snakes curling up into a figure-8, not quite meeting each other at the top for a kiss. Some of the figure-8s are actually twisted into shape, while others just welded the two snake heads on top of a ring A polished silver statue of the God Mercury completely in the nude, reaching out His right hand, and holding the caduceus against His shoulder with the left. The caduceus is a slender rod with a ball on top. The snakes are silver wire that form an oblong figure-8. The wire twists around at both the base and in the middle where it forms an actual knot. The snake heads are small golden ovals at the ends of the wire that are closed together at the top, and faintly have the details of their faces.
Fig. 8 Collection of southern Italian and Sicilian kerykeia, (5th to 4th cent. BCE).
Fig. 9 Gallo-Roman silver statuette of Mercury with a “wire-wrap” caduceus.
  1. Wings — Wings weren’t originally part of the kerykeion, but in Roman art become typical of the caduceus (perhaps to distinguish between the staff of Mercury and other Gods vs. mortal heralds’ staves). The wings can vary in size and shape, sometimes being like hummingbird or sparrow wings, while other times having a large span like swan wings.
  2. Level of detail — The kerykeion is often shown abstract so that even key details like the snakes or knot cannot really be discerned. This probably owes to the difficulty of rendering such details, especially in small formats like vase paintings. We find actual bronze kerykeia do feature serpents from at least the 5th cent. BCE (cf. fig. 26 & 29), so they are seemingly an original component even if vase paintings do not reflect that. Later Roman frescoes, by contrast, seem more committed to rendering those details.

A smooth, round bronze coin with a cleanly rendered caduceus on it. The caduceus is an abstract rod with an oblong figure-8 perched on top. The figure-8 twists into an actual Hercules' knot in the middle, and is left open, with its round ends not meeting in a kiss. There is a Greek legend inscribed on either side.
Fig. 10 Reverse of bronze coin where the caduceus shows a proper “Hercules’ knot.”
  1. Enclosure — How close the snakes come to meeting in a kiss can vary considerably. Especially in early vase paintings, the top of the kerykeion is shaped like a ring and crescent (like the symbol Taurus), while later on the snakes actually achieve a figure-8, or at least come close to it.
  2. Radius — The curvature of the snakes’ bends were originally circular, but in Roman art they can also be very oblong to the point of being oval or pill-shaped.
  3. Thickness — Frescoes can show rather thin, twisty, even wispy looking caducei, while vase paintings show somewhat more solid looking ones, and sculpted or cast kerykeia were even sturdier than that. However, some small-format metallic figurines have survived with caducei that were made using a wire-wrap technique. This suggests to me that even the most thin and bendy looking caducei in art are not a painter’s invention, but probably represented actual metal working styles that were in use to craft them.
A dark bronze figurine of Mercury on a pedestal with a small tortoise and goat. He wears a full-length chlamys, holds a money bag in His right hand, and a caduceus in His left. The caduceus is a thin rod with a wire coiled around it from the ground up, forming both its wings and its snakes which tie in an elegant knot and nearly kiss at the top of their figure-8. A bronze figurine of a fully nude, contrapposto Mercury with large wings in His hair and the chlamys draped over His left arm. He holds a money bag in His right hand and the caduceus against his shoulder in His left. The caduceus is a short rod that's been swallowed up in the mangled remains of wire that still somewhat show the loops and knots of the snakes.
Fig. 11 & Fig. 12 Bronze statuettes of Mercury found in Germany with wire-wrap caducei, c. 2nd and 3rd centuries CE.

Ancient vs. modern

The caduceus is ubiquitous even in modern times, albeit with a transformed design that has minimal resemblance to the caducei of antiquity. Probably the only modern context where we find the original caduceus preserved would be in a very abstract form for the astrological and alchemical signs of Mercury:

An irregular shaped brass colored coin, heavily worn with patina, showing a caduceus in the middle of a ring and circular legend that is illegible. The caduceus is a staff with small, faintly visible wings towards the top, an oblong oval over the top of the staff, and squashed horseshoe shape above that. A plain black unicode character of the symbol for Mercury on a white background. The symbol is like a plus sign with a circle on top, and an upwards facing crescent above that.
Fig. 13 Lydian bronze coin with caduceus on the reverse, c. 2nd cent. CE.
Fig. 14 Unicode symbol for Mercury, c. 1993 CE.

Instead, the modern caduceus has basically been inverted, with enlarged wings perched on top and the two snakes coiling loosely around the rod below in a double-helix, usually tapering as they go down:

A colorful Baroque fresco of Hermes soaring through the clouds, away from the viewer, with a crimson cloak billowing around His midriff. In His left hand is the golden caduceus of the modern style — that is, with a pair of wings perched at the top of the staff and the two snakes coiling in a double-helix down the rod. A simple black clipart of the modern caduceus, which shows a large pair of wings at the top of the staff and two snakes coiling beneath it in a double-helix down the rod.
Fig. 15 Detail of Hermes from an 18th century Italian palace fresco.
Fig. 16 Clipart of a modern caduceus.

While I’ve yet to find an explanation for why this transformation took place, it provides a useful diagnostic for identifying whether an artifact is actually ancient or not (sometimes Renaissance and Modern bronzes of Mercury get mistaken as Roman). Occasionally, genuinely ancient statues are displayed in museums with the modern caduceus, but those are the result of latter-day (usually Renaissance to 17th century) “restorations.”

The modern design of the caduceus stems from Renaissance art, where the double helix snakes were firmly established from the beginning, albeit often without wings. There seem to be few depictions of Mercury in the preceding Medieval era, but the few that I’ve found seem to supply Him with a plain rod, or mace. Both instances could reflect artists producing designs based solely on Classical literary sources available to them, almost all of which did not elaborate on the visual details of the conventional caduceus.

However, there are one or two artifacts from Late Antiquity that might point to a much older visual history for the “double-helix” design:

The first is a Corinthian capital from Auxerre, France. It once had three Gods and a Goddess on its four faces, but now only Mercury remains. It bears the overall appearance of an ancient Roman capital, albeit with a couple details that call its periodization into question. The first is obviously the double-helix caduceus, for which we have no other examples of in Roman Gaul. The second is the hairstyle: Roman Gaulish sculptures of Mercury with enough size and detail always show Him with very curly hair, usually rendered with spherical curls. The combed-straight hair on this piece makes it incredibly suspicious, to me.

Mercury’s overall style here looks reminiscent of one of Raphael’s depictions (e.g., from his “Loggia of Psyche”). And there are possibilities for why even a Renaissance artifact could wind up so fragmented (Huguenots destroyed Catholic buildings when they took over the city in 1567). But there is one other artifact of provable antiquity that leaves open the possibility that a sculpture with this style caduceus could be authentic:

Photo of one side of a square, limestone Corinthian capital with the upper left corner smashed off. The upper body of the God Mercury emerges from the acanthus leaves below with a soft smile on His lips, large almond shaped eyes, short straight hair, and a small petasos on His head. His nose is broken off. His right hand is held out to the side with a faint remnant of what was probably a money bag. His left hand upholds the caduceus, which has no wings. Its two snakes coil in a double helix that forms three loops.
Fig. 17 A French column capital showing Mercury with a “double-helix” caduceus. Found in 1789, but of unknown date.

A remarkable 4th century CE Spanish mosaic at Casariche shows the “double helix” type caduceus clear as day. The Casariche design is provably authentic, as it was discovered in 1986 and documented in situ by archaeologists. There are no signs that the Casariche site remained in use past the Roman period, so later alterations or repairs could not explain its design, either.

Interestingly, both works probably post-date the Christianization of their locales (the Casariche mosaic is 4th century, and Auxerre was evangelized rather early with bishops being sent there since 258 CE). So it would be interesting to consider whether Christianity had any influence on the redesign of the caduceus for one reason or another, although we may never discover how or why the change occurred.

Fig. 18 4th cent. CE Casariche mosaic of Mercury with “double-helix” caduceus.
Fig. 19 Illustration from 15th cent. Italian manuscript.

The caduceus doesn’t reemerge in the surviving art record, as far as I could find, until over a thousand years after the Casariche mosaic, when we finally see it again in a 15th century manuscript (fig. 36), predictably with a double-helix design. The caduceus’ use in art grows very common thereafter.

Caduceus as a Peace Sign

Whose hand contains of blameless peace the rod, Corucian, blessed, profitable God;

— Orphic Hymn to Hermes 9
[Mercury] threw his staff down between the two [snakes] and, lo, they left off fighting; and so he said of the staff that it was appointed to make peace.

— Hyginus 8
Roman silver coin showing a hand shake in front of a caduceus. Beneath the image is the name Albinus Bruti F in rustic capitals. A dull gray Roman coin with hands shaking in front of a caduceus and ears of grain. Letters in a circle around the image are partly worn off and unclear. What's visible looks like BPOTCOS around the top, and SC below.
Fig. 20 & Fig. 21 Reverse of Roman Denarii, showing hands shaking over a caduceus, c. 48 CE. and 138 CE.
Fig. 20 was probably promoting Caesar’s rhetoric of reconciliation during the Civil War.

While largely forgotten nowadays, the caduceus was widely understood in its time as a symbol for Peace. Authors often credit the caduceus’ power to end vitriol and fighting to its visual symbols, the circumstances of its creation, and of course the power of Mercury or Hermes. This is no doubt true, but there are no less interesting mundane reasons for why caducei probably became associated with Peace, as well.

Naturally, heralds were responsible for delivering the news of ceasefires and peace accords. As Servius explains, even the men in peace envoys who negotiated such agreements carried the caduceus. It makes sense that anyone who needed to prove their authority at the negotiating table would either carry the instrument, or be accompanied by someone who does. And as they would possibly have to travel through hostile territory to get there, the caduceus could help assure their protection. Much like noncombatants today who mark themselves with the Red Cross, or blue flak jackets emblazoned with “Press,” the caduceus would have played a part in protecting the bearer from attack — i.e., “don’t shoot the messenger.”

All of this naturally converges to make the caduceus a symbol of Peace, one that was minted on coins to advertise policies of reconciliation, or tout the Pax Romana where it is literally wielded by Pax Herself.

The serpents coiled round the [caduceus] … are a symbol of the fact that even savage men are charmed and bewitched by [Hermes], who loosens the conflicts between them and binds them with a knot which is difficult to untie. For this reason the caduceus appears to be a symbol of peace-making.

— Cornutus 10
This is the explanation of this wand: Mercury is called both god of speech and the spokesman of the gods; thus the rod separates the serpents i.e. poisons. For instance, warring peoples are pacified by the words of spokesmen. That is why, according to Livy, peace negotiators are called caduceators. That is to say, just as wars used to be declared by fetial priests, so peace was made by caduceators.

— Servius 11
A silver Roman coin showing the Goddess without wings facing three quarters forward, upholding a caduceus in Her right hand. Behind her is a barrel with a large flame above it, and all around the image is a giant laurel. On the lower left side the coin by the Goddess the legend simply says PAX. A gold roman coin with the winged Goddess Pax. Her back is three quarters away from the viewer, as She looks down over Her shoulder at a serpent on the ground that She touches with the caduceus She wields in Her left hand. The legend above says PACI AUGUSTAE.
Fig. 22 & Fig. 23 Reverse of coins showing the Goddess Pax with a caduceus, c. 28 BCE & 42 CE.

Figures

  1. “Punishment of Ixion,” 4th style (60-79 CE) Pompeiian fresco from House of the Vettii. (Source). ￪
  2. Bronze kerykeion, from Longane (Sicily), c. 450-420 BCE. (Source). ￪
  3. Bronze caduceus from Centum Prata (Switzerland), c. 1st to 4th cent. CE. Stadtmuseum, Rapperswil. (Source). ￪
  4. Attic red figure attributed to the Berlin painter, c. 480-470 BCE. See entry at Musée du Louvre for more detail. (Image source). ￪
  5. Attic Red-figure skyphos attributed to the Macron painter, c. 480 BCE. See entry at Musée du Louvre for more detail. (Image source). ￪
  6. Fourth Style fresco from the Temple of Isis, Pompeii, c. 1st cent. CE. Museo Archeologico Nazionale, Naples (source). ￪
  7. Small bronze caduceus, 1st cent. CE. See entry at Museum for Kunst and Gewerbe Hamburg for image source and details. ￪
  8. Collection of southern Italian and Sicilian kerykeia, 5th to 4th cent. BCE. See individual entries at Museum for Kunst and Gewerbe Hamburg for more detail. (Image source). ￪
  9. Silver and gold-leaf statuette (56 cm) from the Berthouville Treasure, 1st to 2nd cent. CE. See entry at Bibliothèque nationale de France for more detail. (Image source). ￪
  10. Bronze Bactrian coin of Demetrius I (c. 200-180 BCE). (Image source). ￪
  11. Roman bronze statuette of Mercury from Obernburg am Main, c. 2nd cent. CE. Archäologischen Staatssammlung in München. See German-language article for more info and photos. (Image source). ￪
  12. Roman bronze statuette of Mercury, found at the necropolis in Reinheim, c. 3rd cent. CE. Museum für Vor- und Frühgeschichte des Saarlandes. See German-language entry at Museen in Saarland for more detail and photos. (Image source). ￪
  13. Bronze coin from Sardis (Turkey), c. 140-144 CE. See entry at Digital Coin Cabinet of the Institute of Classical Archaeology of the University of Tübingen for more details. (Image source). ￪
  14. Unicode character for the astronomical and astrological symbol of Mercury. (Image source). ￪
  15. Detail of a fresco by Giovanni Battista Tiepolo, from the Palazzo Clerici, Milan, c. 1740 CE. (Image source). ￪
  16. Clipart of a modern caduceus. (Source). ￪
  17. Limestone capital of Mercury, Apollo, Mars, and unknown Goddess, date unknown. Discovered near the lock of the Bâtardeau in Auxerre, 1789. See entry at the Corpus RBR for more detail. (Image source). ￪
  18. Juicio de Paris mosaic from the Villa del Alcaparral in Casariche (Spain), c. 4th cent. CE. (Source). ￪
  19. Illustration of Hermes by Ciriaco d'Ancona, Italy, c. 1474 CE. Oxford, Bodleian Library MS. Canon. Misc. 280. ￪
  20. Roman denarius, c. 48 CE. (Image source). ￪
  21. Rome mint coin, c. 138 CE. (Image source). ￪
  22. Ephesus mint tetradrachm, c. 28 BCE. (Image source). ￪
  23. Aureus, c. 41-42 CE. (Image source). ￪

References

  1. Iliad book 24. Homer. 8th century BCE.
  2. Thucydides 1.53.
  3. Odyssey book 24. Homer. 8th century BCE.
  4. Hymn 4 to Hermes. Homer. 6th century BCE.
    • The Homeric Hymns and Homerica with an English Translation. H.G. Evelyn-White (Trans.) 1914. ￪
  5. Bibliotheca 3.10.2. Apollodorus. 1st or 2nd cent. CE.
    • Apollodorus, The Library. Sir James George Frazer (Trans.) 1921. ￪
  6. Siebert Gérard. « L’invention du caducée. » In: Ktèma : civilisations de l'Orient, de la Grèce et de Rome antiques, N°21, 1996. Hommage à Edmond Frézouls – III. pp. 344-345. ￪
  7. Saturnalia 1.19.16. Macrobius, c. 431 CE.
    • The Saturnalia. Percival Vaughan Davies (Trans.), Columbia University Press, 1969. ￪
  8. De Astronomia, Gaius Julius Hyginus, 27 BCE – 14 CE.
  9. Orphic Hymn to Hermes. 2nd — 3rd cent. CE.
  10. Ἐπιδρομὴ τῶν κατὰ τὴν ἑλληνικὴν θεωρίαν παραδεδομένων (Epidromē tōn kata tēn hellēnikēn theōrian paradedomenōn, better known as, Theologiae Graecae Compendium, or “Compendium of Greek Theology”). Lucius Annaeus Cornutus, c. 1st cent. CE.
  11. Commentaries on the Aeneid, 4.242, Servius, turn of the 4th to 5th cent. CE.
    • Latin text available at Perseus Tufts: Maurus Servius Honoratus. In Vergilii carmina comentarii. Servii Grammatici qui feruntur in Vergilii carmina commentarii; recensuerunt Georgius Thilo et Hermannus Hagen. Georgius Thilo. Leipzig. B. G. Teubner. 1881.
    • English translation from McDonough, C. M., Prior, R. E., Stansbury, M. (2004). Servius' commentary on Book four of Virgil's Aeneid : an annotated translation, p. 57. ￪