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Unraveling the Mystery of the Roman Dodecahedron

Among the myriad artifacts left behind by the ancient Romans, few are as mysterious and captivating as the Roman dodecahedron.

Unraveling the Mystery of the Roman Dodecahedron
A Roman dodecahedron, set amidst a hoard of ancient coins. Illustration: DALL-E

Among the myriad artifacts left behind by the ancient Romans, few are as mysterious and captivating as the Roman dodecahedron. These small, hollow objects, made of copper alloy or stone, (the stone ones do not have holes, or knobs) and featuring a geometric design with twelve flat faces, each face having a circular hole of varying diameter, have puzzled archaeologists and historians for centuries. 

Discovery and Distribution

Roman dodecahedra have been found scattered across the territories of the former Roman Empire, from Hungary to Great Britain and from the Rhine to the north of Italy. The widespread discovery of these objects indicates their importance or utility in Roman society, yet no written records have been found to explain their function or significance.

The discovery of the first dodecahedron dates back to 1739, in Aston, Hertfordshire and to date, over 116 of these artifacts have been unearthed across a wide geographical range, spanning from northern England to Hungary. However, a significant concentration of finds has been in Gaul, especially within the Rhine basin area, encompassing modern-day Switzerland, eastern France, southern Germany, and the Low Countries. The discovery of some dodecahedrons in coin hoards suggests they were highly valued by their owners. The majority of these finds have been dated back to the 2nd and 3rd centuries A.D.

In 2023, a well-preserved dodecahedron was unearthed by hobbyist archaeologists in Norton Disney, a quaint village in Lincolnshire, UK. This find increased the count of such artifacts discovered in Roman Britain to 33.

Two ancient Roman bronze dodecahedrons and an icosahedron
Two ancient Roman bronze dodecahedrons and an icosahedron (3rd c. AD). Credits: Kleon3, CC BY-SA 4.0 DEED

These artifacts vary in size, measuring between 4 and 11 centimeters (1.6 to 4.3 inches) in diameter. Additionally, an object previously identified as a dodecahedron was correctly recognized as an icosahedron following its unearthing near Arloff, Germany. This icosahedron is now exhibited at the Rheinisches Landesmuseum in Bonn.

The distribution of known dodecahedrons is notably specific, with all discoveries made within regions under Roman control and populated by Celtics. This pattern supports the idea that these objects were unique to the Gallo-Roman culture, born from the interactions between the Celts in Gaul and their Roman conquerors.

In the 1960s, archaeologists discovered similar artifacts along the Maritime Silk Road in Southeast Asia. These versions were smaller and fashioned from gold. They seem not to predate the Gallo-Roman dodecahedrons and could indicate the extent of Roman cultural influence on the ancient Indochinese kingdom of Funan. 

Speculated Functions

Interestingly, there are no existing records from the Roman Empire that mention Roman dodecahedra directly. Nonetheless, some of these objects have been discovered alongside coin hoards, suggesting they were considered valuable. The majority of dodecahedra have been unearthed in the northwestern regions of the Roman Empire, areas rich in Celtic culture, across diverse settings such as military encampments, theaters, temples, residential buildings, and burial sites.

Pentagon dodecahedron in bronze
Pentagon dodecahedron in bronze 150 to 400 AD. Public domain

Numerous hypotheses have been proposed regarding the function of Roman dodecahedra. They might have served as scientific tools for measuring distances or sizing up distant objects. Another possibility is that they were employed in agricultural planning, specifically in determining the optimal sowing period for crops.

The Norton Disney group believes that these theories are unlikely.

“A huge amount of time, energy and skill was taken to create our dodecahedron, so it was not used for mundane purposes,” writes the group, adding: “They are not of a standard size, so will not be measuring devices. They don’t show signs of wear, so they are not a tool.”

Rather than aligning with other theories, the consensus among certain scholars is that dodecahedrons were utilized for religious or ritualistic reasons. As highlighted by Smithsonian magazine, specialists at Belgium’s Gallo-Roman Museum suggest these items were part of magical practices. This theory could account for the lack of mention of dodecahedrons in historical texts, given that the Roman Empire's later adoption of Christianity led to prohibitions against magic. Consequently, those engaged in such practices would have been compelled to conceal their rituals and any associated items.

In 1982, an ornately decorated Roman dodecahedron was unearthed near the Cathedral of Saint-Pierre in Geneva. This particular dodecahedron, inscribed with zodiac names, bolsters the hypothesis that these objects could have been employed for astronomical or astrological purposes.

Candlestick Holders

One theory suggests that the dodecahedra were used as candlestick holders. The varying hole sizes could accommodate different candle diameters, and the object itself could cast interesting shadows, possibly used in religious or ceremonial contexts.

Dodecahedron, 1st to 4th century, bronze
Dodecahedron, 1st to 4th century, bronze , Hunt Museum, Limerick, Ireland. Public domain via Hunt Museum

Measurement Devices

Another hypothesis posits that the dodecahedra served as sophisticated measurement tools. The different diameters of the holes could have been used to gauge distances or to calculate agricultural planting dates, aligning with the Roman focus on engineering and agriculture.

Religious and Mystical Objects

Some scholars speculate a religious or mystical purpose, perhaps as objects dedicated to a deity or used in rituals. The geometric perfection of a dodecahedron, aligning with the Romans' interest in geometry and the cosmos, might symbolize the universe's harmony.

Toys and Educational Tools

A simpler explanation is that these objects were toys or educational tools for teaching geometry and mathematics. The tactile nature of the dodecahedra and their intriguing design could have made them effective for engaging young minds.

Military Applications

A less popular but intriguing theory is that the dodecahedra were used by the Roman military, possibly as range-determining devices for slinging projectiles or other forms of ancient warfare engineering.

Despite various theories, no single explanation has been universally accepted by the scholarly community. The Roman dodecahedron remains a subject of debate, illustrating the gaps in our understanding of daily life in the ancient Roman world.

For those interested in finding out more about the Roman dodecahedron, we hope you’ll enjoy this video: