Roman dodecahedron

Roman dodecahedra are cast in metal,{{cite journal|last=Alexander|first=James|title=A Roman Villa at Newhall, Harlow, Essex|journal=Archaeology International|year=2023|volume=26|pages=212–213|doi=10.14324/AI.26.1.15 |doi-access=free}} usually a copper alloy, although one silver example is known.{{cite book|last=Grüll|first=Tibor|chapter=The Enigma of the Dodecahedron|year=2016|title=From Polites to Magos|editor-last=Szabó|editor-first=Ádám|page=148}} 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 to 11 cm; the holes in their faces have diameters ranging from 6 mm to 40 mm.{{cite book|last=Grüll|first=Tibor|chapter=The Enigma of the Dodecahedron|year=2016|title=From Polites to Magos|editor-last=Szabó|editor-first=Ádám|pages=148–149}} The lightest known example weighs 35 grams; the heaviest 1000 grams.{{cite book|last=Grüll|first=Tibor|chapter=The Enigma of the Dodecahedron|year=2016|title=From Polites to Magos|editor-last=Szabó|editor-first=Ádám|page=149}} Most are decorated with circles, lines, and dots, but no letters or numbers are known to be marked on any of the objects.{{cite book|last=Grüll|first=Tibor|chapter=The Enigma of the Dodecahedron|year=2016|title=From Polites to Magos|editor-last=Szabó|editor-first=Ádám|page=150}} One dodecahedron was found in a tomb alongside a bone object which might have been a kind of handle; however it was in too bad a condition to excavate and preserve.{{cite book|last=Grüll|first=Tibor|chapter=The Enigma of the Dodecahedron|year=2016|title=From Polites to Magos|editor-last=Szabó|editor-first=Ádám|pages=152–153}}

The archaeological context in which the dodecahedra have been found is often uncertain.{{cite journal|first1=Gérard|last1= Guillier |first2=Richard |last2=Delage |first3=Paul-André |last3=Besombes|title=Une fouille en bordure des thermes de Jublains (Mayenne): enfin un dodécaèdre en contexte archéologique !|journal=Revue archaéologique de l'Ouest|year=2008|volume=25|issue= 25 |pages= 269–289 |doi=10.4000/rao.680}} Where it is known, the context is commonly military or funerary;{{cite journal|title=Un dé à jouer dodécaédrique en os découvert à Esvres (Indre-et-Loire)|year=2024|first1=Jean-Philippe|last1=Chimier|first2=Alain Ferdière|last2=Olivier Marlet|first3=Grégory|last3=Silberstein|journal=Instrumentum: Bulletin du groupe de travail européen sur l'artisanat et les productions manufacturées dans l'Antiquité|volume=59|page=40}} 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.{{cite journal|last=Duval|first=Paul-Marie|title=Comment Décrire les Dodécaèdres Gallo-Romains, en Vue d'une Étude Comparée|year=1981|journal=Gallia|volume=39|issue=2|pages=195–200 |doi=10.3406/galia.1981.1829 |jstor=43605135|url=https://hal.archives-ouvertes.fr/hal-01940681/file/Gallia_1981_39-2_195-200_DUVAL.pdf }}

File:2018 Rheinisches Landesmuseum Bonn, Dodekaeder & Ikosaeder.jpg, Germany]]

The first dodecahedron was found in 1739 in Aston, Hertfordshire, England. Since then, at least 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.{{cite news |last1=Stavrou |first1=A |title=Amateur archaeologist discovers bizarre Roman object that has baffled for centuries |url=https://www.independent.co.uk/news/science/archaeology/roman-dodecahedron-archaeology-sheffield-b2482023.html |access-date=20 January 2024 |work=The Independent |date=20 January 2024}} It was on display at the Lincoln Museum, Lincolnshire until October 2024.{{cite news |title=Roman dodecahedron that baffled experts stays on show in Lincoln |url=https://www.bbc.co.uk/news/articles/cwyjrvnj93jo |access-date=28 August 2024 |work=BBC News |date=27 August 2024}}

The purpose of Roman dodecahedra has been much debated:{{cite journal|last1=Coombe|first1=Penny|last2=Henig|first2=Martin|last3=Adams|first3=Kurt|last4=Gilmour|first4=Brian|last5=Pearce|first5=John|title=The Gloucester Hoard of Roman Bronze|journal=Britannia|year=2020|volume=51|page=260|doi=10.1017/S0068113X20000501 }} 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.{{cite book|last=Grüll|first=Tibor|chapter=The Enigma of the Dodecahedron|year=2016|title=From Polites to Magos|editor-last=Szabó|editor-first=Ádám|page=151}} 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.

Several dodecahedra were found in coin hoards, suggesting either that their owners considered them valuable objects, or that their use was connected with coins — as, for example, for easily checking coins fit a certain diameter and were not clipped. It has been suggested that they might have been religious artifacts, or even fortune-telling devices. This latter speculation is based on the fact that most of the examples have been found in Gallo-Roman sites. It has also been suggested that they might have been an object to test the skill of a metalsmith, perhaps as part of a portfolio to demonstrate their capabilities to customers or as a way to qualify for a certain status in a collegium (guild). This speculation is based on the historic cost of bronze and the level of skill necessary to cast such an object. Some 19th-century antiquarians speculated that they might be weapons, such as the head of a mace or a metal bullet, but other scholars have suggested that the dodecahedra are too light to make an effective weapon.

A Roman icosahedron has also been discovered after having long been misclassified as a dodecahedron. This icosahedron was excavated near Arloff in Germany and is currently on display in the Rheinisches Landesmuseum in Bonn. In 2009, metal-detectorists in France reported the discovery of an object at Saint-Trivier-de-Courtes, similar to the Roman dodecahedra but spherical with triangular and pentagonal holes.{{cite book|last=Grüll|first=Tibor|chapter=The Enigma of the Dodecahedron|year=2016|title=From Polites to Magos|editor-last=Szabó|editor-first=Ádám|page=154}} A solid silver Roman dodecahedron was discovered in Geneva in 1982; each face is inscribed with the name of one of the signs of the zodiac.{{cite book|last1=Maor|first1=Eli|last2=Jost|first2=Eugen|title=Pentagons and Pentagrams: An Illustrated History|publisher=Princeton University Press|year=2022|page=115}}

Smaller dodecahedra with the same features (holes and knobs) and made from gold have been found in South-East Asia along the Maritime Silk Road and the earliest items appear to be from the Roman epoch. Examples include those uncovered in Óc Eo, Vietnam, by Louis Malleret, who concluded that the objects represented the influence of Mediterranean trade on the Funan economy.

{{reflist|refs=

{{cite journal | last=Hill | first=Christopher | title=Gallo-Roman Dodecahedra: A Progress Report | journal=The Antiquaries Journal | publisher=Cambridge University Press (CUP) | volume=74 | year=1994 | issn=0003-5815 | doi=10.1017/s0003581500024458 | pages=289–292| s2cid=161691752 }}

{{cite web |last1=Metcalfe |first1=Tom |title=The Mysterious Bronze Objects that Have Baffled Archaeologists for Centuries |url=https://getpocket.com/explore/item/the-mysterious-bronze-objects-that-have-baffled-archaeologists-for-centuries |website=Pocket |publisher=Mental Floss |accessdate=17 September 2019 |date=August 6, 2018}}

{{cite journal | last=Guggenberger | first=Michael | title=The Gallo-Roman Dodecahedron | journal=The Mathematical Intelligencer | publisher=Springer Science and Business Media LLC | volume=35 | issue=4 | date=2013-10-03 | issn=0343-6993 | doi=10.1007/s00283-013-9403-7 | pages=56–60| s2cid=122337773 }}

{{cite arXiv|last=Sparavigna|first=A.|year=2012|title=Roman dodecahedron as dioptron: Analysis of freely available data|class=physics.pop-ph|eprint=1206.0946}}

{{cite book|last=Greiner |first=Bernhard A.|year=1996|section=Römische Dodekaeder: Untersuchungen zur Typologie, Herstellung, Verbreitung, und Funktion|language=de|title=Carnuntum Jahrbuch 1995|pages=9–44}}

{{cite book|last=Henig|first=Martin|year=1984|title=Religion in Roman Britain|publisher=Routledge|isbn=0-7134-6047-4|page=128}}

{{cite magazine| last=Kilford|first=L.J.P.|date=December 2004|title=A mathematical tourist in Germany|magazine=Mathematics Today|volume=40|issue=6|page=204}}

{{cite journal |last=Malleret |first=Louis |year=1961 |title=Les dodecaedres d'or du site d'Oc-eo|language=fr|trans-title=The gold dodecohedrons from the Oc-eo site |journal=Artibus Asiae|volume=24 |issue=3–4 |pages=343–350 |issn=0004-3648 |doi=10.2307/3249235|publisher=JSTOR |jstor=3249235}}

{{cite book |last1=Spencer |first1=David J. |title=Knitting technology: a comprehensive handbook and practical guide |date=2001 |publisher=Technomic |location=Lancaster, Pa. |isbn=9781855737556 |edition=3rd}}

{{cite book |last1=von Schmoller |first1=Gustav |title=Die Strassburger tucher- und weberzunft: Urkunden und darstellung nebst regesten und glossar. Ein beitrag zur geschichte der deutschen weberei und des deutschen gewerberechts vom XIII.-XVII. jahrhundert |date=1879 |publisher=Verlag von Karl J. Trübner |location=Strassburg |url=https://books.google.com/books?id=5u5NAAAAMAAJ |access-date=27 January 2023 |chapter=67. Rathsentscheidung in einem Streite der Tuchersunft und der Zunft zum Spiegel. dass das Hosenstricker-Handwerk ze der erstern gehöre. 1535.}}

{{cite book |last1=Rutt |first1=Richard |title=A History of Hand Knitting |date=1987 |publisher=Interweave Press |location=Loveland, Colo. |isbn=0934026351 |edition=U.S. |url=https://archive.org/details/historyofhandkni0000rutt/ |access-date=27 January 2023 | page=22}}

{{cite book |last1=Artmann |first1=Benno |title=Euclid – the creation of mathematics |date=1999 |publisher=Springer |location=New York |isbn=978-0-387-98423-0 |page=303 |url=https://archive.org/details/euclidcreationof0000artm/}}

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{{Spoken Wikipedia|Roman_dodecahedron.ogg|date=2019-8-29}}

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• [https://web.archive.org/web/20110612143656/http://www.foxnews.com/scitech/2011/06/10/dodecahedrons-purpose-remains-mystery/ "History Mystery: Ancient Dodecahedron's Purpose Remains Secret"] by Alexandria Hein, Fox News, June 10, 2011

Category:Archaeological artefact types

Dodecahedron

Category:Platonic solids

Category:1739 archaeological discoveries

Dodecahedron

Category:Ancient Roman technology