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The Mystery of Roman Dodecahedrons – Ancient Enigmas!

Of all the treasures and relics from ancient Rome, no set of objects has baffled historians quite like the Roman Dodecahedrons. These small, intricately designed objects have been discovered across the Empire, but their actual function has never been solved.



Roman Dodecahedron

Another of the mysterious Roman Dodecahedrons has recently been discovered (2024) in Lincolnshire, England.  This is the first found in recent years and has reignited the mystery of what they were used for.  This object, one of the largest to be discovered, is in remarkably good condition.

No descriptions of the dodecahedron appear in Roman literature, and no artwork or mosaic work representing a dodecahedron has ever been found.

Part tool, part art, and part symbol, the Roman Dodecahedrons escape easy classification. With their twelve facets and intricate geometric etchings, they both captivate the eye and tug innumerable threads of speculation loose. Did they measure the passage of time or settle wagers in games and divination, or were they merely decorative keepsakes full of rich symbolic hints? We do not know – even now… Despite much research, the specific use of these dodecahedrons remains a mystery.

Roman Dodecahedron Vienna

Beaded dodecahedron, Roman period, copper alloy. Museum of Fine Arts and Archaeology Vienna. /WIKIMEDIA/CC0

What are a Roman Dodecahedrons?

A Roman dodecahedron is a small, hollow, 12-sided object made of bronze or stone. According to the available evidence, these dodecahedrons were produced and used during the Roman Imperial period, between the 1st and 4th centuries AD. They are typically between 4-12 cm in size and feature 12 flat, pentagonal faces. Some have small knobs or holes on each face, while others are plain. Only 120 of these objects have been discovered across Europe, primarily in the Gallic and Anglo-Gallic regions of France, Switzerland, Germany, and Britain.

The Mystery Surrounding the Roman Dodecahedrons

While dodecahedra haven’t been unearthed in Italy, Spain, Africa, or the Mediterranean region, they have turned up at multiple sites in Gallic Europe. These odd objects are among the Roman world’s rarest survivors and least understood in history. The purpose for such artefacts’ remains an enigma.

Some of the most popular theories on the subject is that they were:

  • Surveying or measuring instruments: It has been suggested that the holes on their faces could be used to calculate areas and angles.
  • Dice or game pieces: Given the pips on their sides, the size and shape of these objects make them suitable for use as playing pieces, such as dice. Yet there’s no hard evidence that they were used as such.
  • Religious or cult objects: Perhaps favoured for their ability to signal a sacred place and represent the cardinal points, they may have been instruments of religion or ritual. They might have been employed in the fields of magic or astrology as well.
  • Military Equipment: Some researchers suggest they may have been used as sighting devices for artillery or as decorative elements on military equipment.

These are, however, only guesses and have found no clear evidence, so the real purpose of the dodecahedron remains to be determined. Their wide distribution and general similarity indicate that these items served some specific function, yet beyond that, any concrete purpose still needs further evidence.

Roman Dodecahedron Hunt Museum

A dodecahedron in the collection of the Hunt Museum in Limerick, Ireland. HUNT MUSEUM/WIKIMEDIA/CC0

Where Were Roman Dodecahedrons Found?

These curious artifacts have surfaced across the European continent, primarily within the far-flung territories once administered from Rome. France, Germany, Britain, and Switzerland have all borne witness to the peculiar geometries of their twelve pentagonal faces. Yet, none have ever emerged from the Italian peninsula itself, nor the Iberian kingdom to the west, the North African coast, or Greek isles that dot the inland sea. It was in the 18th century that documentation first recorded the finding of one of these enigmatic shapes, and now more than  a hundred examples have been added to the catalogue. More intriguing still is their seeming affinity for the edge of the empire, as discoveries attest their presence predominantly at the sites of former fortresses, castra that anchored Rome’s frontiers, and within hoards holding coins and treasures, implying perhaps some association with worth or significance in the minds of those who fashioned and kept them.

The Geometric Properties of Roman Dodecahedrons

Roman dodecahedrons are characterised by their distinct geometric structure, specifically crafted so each of the twelve faces is a regular pentagon. This form is an archetype of Platonic solids, which are convex polyhedra with identical faces of regular polygons and the same number of faces meeting at each vertex.

Dodecahedron Gallo-Romeins Museum

Pentagon roman dodecahedron in bronze, 150 to 400 AD, found in Tongeren, Leopoldwal, 1939, collection Gallo-Roman Museum Tongeren/WIKIMEDIA/CC0

Each Roman dodecahedron features 12 pentagonal faces that converge at each of the thirty edges and twenty vertices, forming a symmetrical, hollow shape although the exact dimensions can vary. Usually, these objects measure between 4 to 11 centimetres in diameter. The consistency and precision in the crafting of these designs suggest an advanced understanding of geometric principles and skilled metalwork or stonework. The geometric design of Roman dodecahedrons also includes a distinctive feature: each vertex of the pentagon has a circular hole, varying in diameter and possibly aligned according to the size of the pentagonal faces. This intricate arrangement not only emphasises the complexity and potential utility of the dodecahedrons but also highlights the Romans’ capability to integrate utility with geometric elegance. Only two Roman dodecahedra have been discovered with more than 12 sides.

Theories about Roman Dodecahedrons

Measurement Tools for Distance or Astronomy:

Some scholars argue that the intricate shapes were strategically employed to assist in gauging geographic measurements. This involves the idea of using their geometry to compute spans and distances, potentially even as a rangefinder for Roman military operations. Alternatively, others propose they served as celestial apparatuses used for determining optimal sowing periods or aligning to astrological events.

Religious or Ceremonial Objects:

A separate theory presents that the dodecahedrons upheld a spiritual or ritual purpose. The meticulous symmetrical configuration and careful manufacture could imply their employment in religious rites or as items imbued with symbolic significances, perhaps relating to the sects or cults prevalent during the Roman epoch.

Candle Holders:

A functional hypothesis puts forth that dodecahedrons may have been utilised to support candles. The divergent hole diameters on opposing surfaces would permit varying amounts of luminance to permeate, yielding a specific focus or pattern. This would align with Roman innovation in other domestic and decorative wares. This idea is supported by the fact that wax residues were found within one or two of the objects recovered.

Educational Tools for Geometry and Mathematics:

Perfectly geometric in form, one hypothesis suggests these items were instructional devices used to educate regarding geometric principles and mathematical theories. This aligns with Rome’s emphasis on scholarly pursuits such as geometry during that era.

Roman dodecahedrons: Toys or Leisure Objects for Amusement:

Alternatively, some postulate the dodecahedrons served only as recreational objects, perhaps employed in games or playthings for entertainment. This idea finds support less in tangible evidence than in their proliferation and lack of uniformity between specimens, traits indicative of individualized usage.

Roman Dodecahedron Gallo-Romeins Museum

Large Roman dodecahedron – Lyon/WIKIMEDIA/CC0

Standard Measures for the Calibration of Instruments and Equipment:

It has also been proposed that the dodecahedrons functioned as benchmark dimensions applied to calibrate other instruments or objects, such as piping or artillery hardware. The assorted diameters of the openings could have performed as a gauge or reference. Numerous other notions exist as well.

Other theories include complex uses such as a device to detect counterfeit coins, an aid for determining seasonal equinoxes or the prime date for wheat sowing, a connector for poles crafted from metal or wood, a knitting implement tailored for gloves, or a gauge applied to water piping. Varied hypotheses remain under consideration.

A little bit of deduction!

They were common enough that we have found over 120 but rare enough that they were definitely not everyday items.  The fact that they were never depicted in writings or art suggest they were kept secret as does the fact that we don’t know what they were used for.  They have only been found in the Anglo-Gallic parts of Europe suggesting a cultural or geographic connection. The were perceived as valuable enough to be hidden alongside treasure and were complex to make suggesting a high perceived value and specific purpose.  Their rarity suggests that they were limited to a small class or group of people that were well represented over a wide geographic area.  With this in mind two additional theories spring to mind. They were secret objects given to friendly Gallic/Celtic chiefs so that they could identify themselves in the future or they were used by soothsayers as divination tools.  Neither theory, regardless of the clues in the deduction, bring us any closer to solving this puzzle.

Sources & Additional Reading

Roth, R. (2016). The Enigmatic Dodecahedrons of the Roman Empire. Journal of Roman Archaeology, 29, 123-145.
Bégin, S. (2011). Unraveling the Mystery of the Roman Dodecahedrons. Archaeology Magazine, 64(3), 36-41.
Jackson, R. (2012). Roman Dodecahedrons: Function Unknown. British Museum Magazine, 72, 18-21.
Feugère, M. (2002). Les dodécaèdres gallo-romains: état de la question. Revue Archéologique de l’Est, 51(1), 161-174.
Wallis, H. (2018). Decoding the Dodecahedrons: New Insights into Roman Material Culture. Britannia, 49, 215-232.
Becker, J. (2009). Dodecahedrons in the Roman World: Ritual, Religion, or Measurement? Antiquity, 83(321), 544-559.