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Roman dodecahedron
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Roman dodecahedron
A Roman dodecahedron or Gallo-Roman dodecahedron is a type of small hollow object made of copper alloy that has been cast into a regular dodecahedral shape with twelve flat pentagonal faces. Each face has a circular hole of varying diameter in the middle, the holes connecting to the hollow center, and each corner has a protruding knob. They rarely show signs of wear and do not have any inscribed numbers or letters.
Since the first known example was recorded in 1739, over one hundred such objects have been discovered, dating from the 2nd to the 4th centuries AD. Their purpose or meaning has been long debated but remains unknown.
Roman dodecahedra are cast in metal, usually a copper alloy. They are in the shape of regular dodecahedra, with the addition of a small metal ball at each vertex; each face has a circular hole in the centre. The dodecahedra vary in size from 4–11 cm (1.6–4.3 inches); the holes in their faces have diameters ranging from 6–40 mm (0.24–1.57 inches). The lightest known example weighs 35 g (1.2 ounces); the heaviest 1 kg (2.2 pounds).
The dodecahedra are cast using the lost wax technique. The interior surfaces are left unfinished, though the outsides are well-finished and were probably polished. Most are decorated with circles, lines, and dots, but no letters or numbers are known to be marked on any of the objects. The most common decorative scheme is for two or three concentric circles to be inscribed around the holes.
The metal balls on the vertices of the dodecahedra are not perfectly regular, suggesting that they were made without the use of a mould. They are generally soldered to the body of the dodecahedron, though the example from Carmarthen in the collection of the Society of Antiquaries of London was cast as a single piece, including the balls. One example, found in London, has clusters of three balls at each corner rather than just one.
The first Roman dodecahedron to be recorded was presented to the Society of Antiquaries of London on 28 June 1739 and was reported to have been found in a field in Aston, Hertfordshire, England. Since then, about 130 similar objects have been found in Austria, Belgium, France, Germany, Hungary, Luxembourg, the Netherlands, Switzerland, and the United Kingdom, but not in the Roman heartland in Italy. In 2023, a dodecahedron in excellent condition was found by amateur archeologists in the small village of Norton Disney in Lincolnshire, UK, bringing the total to 33 such objects found on the territory of Roman Britain. It was on display at the Lincoln Museum, Lincolnshire, until October 2024.
The archaeological context in which dodecahedra have been found is often uncertain. Where it is known, the context is commonly military or funerary; other discoveries have been in baths, a theatre, a coin hoard, and on a riverbed. They were mostly made in Gaul between the second and fourth centuries AD. One dodecahedron was found in a tomb alongside a bone object that might have been a kind of handle; however, it was in too bad a condition to excavate and preserve.
The purpose of Roman dodecahedra has been much debated: more than fifty possible explanations have been published. Identifying their purpose with certainty is made more difficult as no mention of dodecahedra has been found in contemporary accounts or pictures. Speculative uses include as a survey instrument for estimating distances to (or sizes of) distant objects, though this is questioned, as there are no markings to indicate that they would be a mathematical instrument; as spool knitting devices for making gloves (though the earliest known reference to spool knitting is from 1535, and this would neither explain the use of bronze, nor the apparently similar icosahedron, which is missing the holes necessary for spool knitting); or as part of a child's toy.
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Roman dodecahedron AI simulator
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Roman dodecahedron
A Roman dodecahedron or Gallo-Roman dodecahedron is a type of small hollow object made of copper alloy that has been cast into a regular dodecahedral shape with twelve flat pentagonal faces. Each face has a circular hole of varying diameter in the middle, the holes connecting to the hollow center, and each corner has a protruding knob. They rarely show signs of wear and do not have any inscribed numbers or letters.
Since the first known example was recorded in 1739, over one hundred such objects have been discovered, dating from the 2nd to the 4th centuries AD. Their purpose or meaning has been long debated but remains unknown.
Roman dodecahedra are cast in metal, usually a copper alloy. They are in the shape of regular dodecahedra, with the addition of a small metal ball at each vertex; each face has a circular hole in the centre. The dodecahedra vary in size from 4–11 cm (1.6–4.3 inches); the holes in their faces have diameters ranging from 6–40 mm (0.24–1.57 inches). The lightest known example weighs 35 g (1.2 ounces); the heaviest 1 kg (2.2 pounds).
The dodecahedra are cast using the lost wax technique. The interior surfaces are left unfinished, though the outsides are well-finished and were probably polished. Most are decorated with circles, lines, and dots, but no letters or numbers are known to be marked on any of the objects. The most common decorative scheme is for two or three concentric circles to be inscribed around the holes.
The metal balls on the vertices of the dodecahedra are not perfectly regular, suggesting that they were made without the use of a mould. They are generally soldered to the body of the dodecahedron, though the example from Carmarthen in the collection of the Society of Antiquaries of London was cast as a single piece, including the balls. One example, found in London, has clusters of three balls at each corner rather than just one.
The first Roman dodecahedron to be recorded was presented to the Society of Antiquaries of London on 28 June 1739 and was reported to have been found in a field in Aston, Hertfordshire, England. Since then, about 130 similar objects have been found in Austria, Belgium, France, Germany, Hungary, Luxembourg, the Netherlands, Switzerland, and the United Kingdom, but not in the Roman heartland in Italy. In 2023, a dodecahedron in excellent condition was found by amateur archeologists in the small village of Norton Disney in Lincolnshire, UK, bringing the total to 33 such objects found on the territory of Roman Britain. It was on display at the Lincoln Museum, Lincolnshire, until October 2024.
The archaeological context in which dodecahedra have been found is often uncertain. Where it is known, the context is commonly military or funerary; other discoveries have been in baths, a theatre, a coin hoard, and on a riverbed. They were mostly made in Gaul between the second and fourth centuries AD. One dodecahedron was found in a tomb alongside a bone object that might have been a kind of handle; however, it was in too bad a condition to excavate and preserve.
The purpose of Roman dodecahedra has been much debated: more than fifty possible explanations have been published. Identifying their purpose with certainty is made more difficult as no mention of dodecahedra has been found in contemporary accounts or pictures. Speculative uses include as a survey instrument for estimating distances to (or sizes of) distant objects, though this is questioned, as there are no markings to indicate that they would be a mathematical instrument; as spool knitting devices for making gloves (though the earliest known reference to spool knitting is from 1535, and this would neither explain the use of bronze, nor the apparently similar icosahedron, which is missing the holes necessary for spool knitting); or as part of a child's toy.
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