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Investigation of the Manufacturing Technology of Complex Copper Alloy Late Roman Coins (240 AD to 395 AD) Using Archaeometallurgy Techniques

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Coinage in the Late Roman Period suffered from severe debasement. From approximately 40% in 240 AD, the silver content dropped to 20% in 250 AD, and by 260 AD, the fineness of the silver denomination had been reduced to just 5% Ag. For the production of these “silver” coins, copper-based quaternary copper–tin–lead–silver alloys were used. Their surface was covered by thin silver plating which was worn off easily during the circulation and use of the coins. Later, the same method was used for a new coin, the nummus, introduced by Diocletian, in his monetary reform (AD 293/4). During the fourth century, the method continued to be in use for the production of debased nummi and other silvered copper alloy coins. Previous analyses of these coins did not solve key technological issues and, in particular, the deployment of quaternary alloys for their production. For the purposes of this project, the British Museum’s Department of Coins and Medals kindly allowed further examination of coins from Cope’s archive, utilizing a range of analytical techniques. This paper presents the outcomes of the metallographic examination of 179 late Roman coins from this archive. As part of this work, a series of experiments were also undertaken to replicate the alloys used in the production of the Roman coins and provide samples to research their microstructure. The examination of the metallographic structures of the quaternary alloys showed that they were similar to the microstructures of the Roman coins demonstrating that some of the coins were in as-cast condition. EPMA and SEM examination of the quaternary alloys confirmed that the structure was as described in the metallographic examination and the distribution of Ag and Pb in the alloy was uniform.

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  1. R.A.G. Carson, Coins of the Roman Empire, 1st edn (Routledge, London and NY, 1990)

    Google Scholar 

  2. K.W. Harl, Coinage in the Roman Economy 300 B.C. to A.D. 700 (The Johns Hopkins University Press, Baltimore and London, 1996)

    Book  Google Scholar 

  3. P.M. Bruun (ed.), Constantine and Licinus A.D. 313–337, vol VII (Spink and Son LTD., London, 1966)

    Google Scholar 

  4. L.H. Cope, C.E. King, J.P. Northover, T. Clay, Metal analyses of Roman coins minted under the Empire, in Occasional Paper, vol 120, (British Museum Press, London, 1997)

    Google Scholar 

  5. L.H. Cope, H.N. Billingham, The composition of 35 Roman Bronze Coins of the period AD 284–363. Bull. Hist. Metall. Group. 1, 1–6 (1967)

    Google Scholar 

  6. R.A.G. Carson, System and product in the Roman Mint, in Essays in Roman Coinage Presented to Harrold Mattingly Oxford (1979), pp. 227–239.

  7. C.H.V. Sutherland (ed.), From Diocletian’s Reform (A.D. 294) to the Death of Maximinus (A.D. 313), vol VI (Spink and Son LTD., London, 1973)

    Google Scholar 

  8. P.H. Webb (ed.), Valerian to the Reform of Diocletian A.D. 253 to 296, vol V (Spink and Son LTD., London, 1927)

    Google Scholar 

  9. D.R. Cooper, The Art and Craft of Coinmaking: A History of Minting Technology (Spink & Son, London, 1988)

    Google Scholar 

  10. G.F. Hill, Ancient methods of coining. Numis. Chron. 5, 1–42 (1922)

    Google Scholar 

  11. D.G. Shellwood, Msc in Kingston Polytechnic, New castle upon Tyne (1975)

  12. J. Knight, A forgotten coin hoard from Monmouthshire Walles. Bull. Board Celtic Stud. (Bwletin y Bwrdd Gwybodau Celtaidd). 32, 417–418 (1985)

    Google Scholar 

  13. W. Malkmus, Addenda to Vermeule’s catalog of ancient coin dies. Part 1. SAN. 17, 80–85 (1989)

    Google Scholar 

  14. W. Malkmus, Addenda to Vermeule’s catalog of ancient coin dies. Part 2. SAN. 18, 16–22 (1990)

    Google Scholar 

  15. W. Malkmus, Addenda to Vermeule’s catalog of ancient coin dies. Part 3. SAN. 18, 40–49 (1991)

    Google Scholar 

  16. W. Malkmus, Addenda to Vermeule’s catalog of ancient coin dies. Part 4. SAN. 18, 72–77 (1992)

    Google Scholar 

  17. W. Malkmus, Addenda to Vermeule’s catalog of ancient coin dies. Part 5. SAN. 18, 96–105 (1993)

    Google Scholar 

  18. C. Vermeule, Minting Greek and Roman coins. Archaeology. 10, 100–107 (1957)

    Google Scholar 

  19. L.H. Cope, Liverpool Polytechnic, Liverpool (1974).

  20. J. Hammer, Der Feingehalt der griechishen und römischen Münnzen (Zeitschrift für Numismatik, 1908)

    Google Scholar 

  21. P.H. Webb (ed.), Valerian to the Reform of Diocletian A.D. 253 to 296, vol V (Spink and Son LTD., London, 1933)

    Google Scholar 

  22. P. Le Gentilhomme, Variations du titre de l’antoninianus au IIIe siècle. Rev. Numis. 6, 141–166 (1962)

    Article  Google Scholar 

  23. L.H. Cope, Roman imperial silver coinage alloy standards: the evidence. Numis. Chron. 6, 107–130 (1967)

    Google Scholar 

  24. L.H. Cope, The argentiferus bronze alloys of the large tetrarchic folles of A.D. 294–307. Numis. Chron. 8, 115–149 (1968)

    Google Scholar 

  25. L.H. Cope, The nadir of the imperial antoninianus in the reign of Claudius II Gothicus, A. D. 268–270. Numis. Chron. 9, 145–161 (1969)

    Google Scholar 

  26. L.H. Cope, H.N. Billingham, The composition of 26 Roman imperial silver and bronze coins minted between A.D.206 and 360. Bull. Hist. Metall. Group. 2, 51–53 (1968)

    Google Scholar 

  27. L.H. Cope, H.N. Billingham, Chemical analyses of some weight-reduced Roman folles minted between AD 307 and 318. Bull. Histor. Metall. Group. 3, 30–31 (1969)

    Google Scholar 

  28. L.H. Cope, H.N. Billingham, The chemical composition of the bronze coinage of Maxentius, AD 306–312. Bull. Histor. Metall. Group. 3, 62–64 (1969)

    Google Scholar 

  29. L.H. Cope, The Metallurgical Analysis of Roman Imperial Silver AND aes Coinage, in Methods of Chemical and Metallurgical Investigation of Ancient Coinage, vol 8, ed. by E.T. Hall, D.M. Metcalf (Royal Numismatic Society, London, 1972), pp.3–47

    Google Scholar 

  30. L.H. Cope, The finess and sequence of the Gallienic Antonianiani, A.D. 259–68. Numis. Chron. 7, 216–219 (1977)

    Google Scholar 

  31. L.H. Cope, Diocletian’s price edict and second coinage reform in the light of recent discoveries. Numis. Chron. 7, 220–226 (1977)

    Google Scholar 

  32. P. Bastien, Le monnayage de l’atelier de Lyon. Dioclétien et ces corégents avant la réforme monétaire (285–294), vol VII (Numismatique Romaine, Wetteren, 1972)

    Google Scholar 

  33. P. Bastien, in Lactance XVII, 1 à 4, et les émissions d' or des Vicennalia de Dioclétien et de Maximien à Ticinum, Aquilée et Nicomédie 253–266 (1976).

  34. P. Bastien, Le monnayage de l’atelier de Lyon 294–316 (Numismatique Romaine, Wetteren, 1980)

    Google Scholar 

  35. P. Bastien, in Le monnayage de l'atelier de Lyon. De la Réouverture de l' atelier par Aurelien à la mort de Carin (fin 274- mi285). Editions Numismatique Romaine, Wetteren (1976).

  36. D. Gibbons, D. Lawson, in The 1968 International Conference, Modern Trends In Activation Analysis. National Bureau of Standards (1968), pp. 226–229.

  37. A. Ravetz, Neutron activation analysis of silver in some late Roman copper coins. Archaeometry. 6, 46–55 (1963)

    Article  Google Scholar 

  38. C.H.V. Sutherland, M.R. Harold, The silver content of Diocletian’s early post-reform copper coins. Archaeometry. IV, 56 (1961)

    Article  Google Scholar 

  39. J.N. Barrandon, Brenot, C. in Les "Dévaluations" a Rome Epoque Républicaine et Impériale 124–145. Collection de L' Ecole Française De Rome, Rome (1975).

  40. J.N. Barrandon, J.P. Callu, C. Brenot, The analysis of Constantinian coins (A.D. 313–340) by non-destructive californium activation analysis. Archaeometry. 19, 173–186 (1977)

    Article  Google Scholar 

  41. C. Morrison, J.N. Barradon, C. Brenot, Composition and technology of ancient and medieval coinages: a reassessment of analytical results. Am. Numis. Soc. Mus. Notes. 32, 181–209 (1987)

    Google Scholar 

  42. G.F. Carter, Chemical Based Roman Coins Augustan Quadrantes, ca 9–4 BC, in Archaeological Chemistry. (ACS Publications, 1978), pp.347–377

    Chapter  Google Scholar 

  43. G.F. Carter, Precision in the X-Ray fluorascence analysis of sixty one augustan quadrantes. J. Archaeol. Sci. 5, 293–300 (1978)

    Article  CAS  Google Scholar 

  44. D.R. Walker, From Augustus to Domitian Part I, in The metrology of the Roman silver Coinage. BAR Supplementary Series 5 (1976)

  45. D.R. Walker, Part II, in The Metrology of the Roman Silver Coinage. BAR Supplementary Series 22 (1977).

  46. D.R. Walker, From Pertinax to Uranius Antonius Part III, in The Metrology of the Roman Silver Coinage. BAR Supplementary Series 40 (1978).

  47. C. King, The alloy content of folles and imitations from the Woodeaton hoard. PACT. 1, 86–100 (1977)

    CAS  Google Scholar 

  48. C.E. King, R.E.M. Hedges, An analysis of some third century roman coins for surface silvering and silver percentage of their alloy content. Archaeometry. 16, 189–200 (1974)

    Article  Google Scholar 

  49. C.E. King, in 10th International Congress of Numismatics, ed. by I.A. Carradice (International Association of Professional Numismatists, London, 1986), pp. 289–292.

  50. C.E. King, J.P. Northover, The Analyses, in Der Münzhort aus dem Gutshof in Neftenbach, vol 16, ed. by H.-M. von Kaenel (Zürcher Denkmalpflege Archäologische Monographien, Zurich, 1993)

    Google Scholar 

  51. M.R. Cowell, The application of chemical, spectroscopic and statistical methods of analysis, in A Survey of Numismatic Research 1978-1984, vol. 2, ed. by M. Price et al. IAPN special publication No 9 (1986), pp. 1022–1040

  52. M.J. Hughes, M.R. Cowell, P.T. Craddock, Atomic absorption techniques in archaeology. Archaeometry 18, 19–37 (1976)

    Article  Google Scholar 

  53. M. Ponting, in The Application of Scientific Methods for Investigating Coins and Coinage, A Symposium Held at the British Museum on 23–24 September 1994 (London, 1994)

  54. M.J. Ponting, in Folles and forgeries: an appraisal of the composition of Roman copper-alloy coinage of the mid-3rd to mid-4th centuries A.D. from Britain. PhD thesis, (University of London, 1994).

  55. L. Pappalardo et al., The new PIXE-alpha spectrometer for the analysis of Roman nummi surfaces. X Ray Spectrom. 42, 33–37 (2013)

    Article  CAS  Google Scholar 

  56. F.P. Romano, S. Garraffo, L. Pappalardo, F. Rizzo, In situ investigation of the surface silvering of late Roman coins by combined use of high energy broad-beam and low energy micro-beam X-ray fluorescence techniques. Spectrochim. Acta Part B At. Spectrosc. 73, 13–19 (2012)

    Article  CAS  Google Scholar 

  57. S. Scrivano et al., An approach to the metallic composition of the Carthage mint coins from the tetrarchic hoard of Tomares (CA. 312 CE). J. Archaeol. Sci. Rep. 44, 103509 (2022)

    Google Scholar 

  58. C. Vlachou-Mogire, Silver amalgam plating and its application in Roman coin production. in 2nd International Conference on Ancient Greek Technology, ed. by Y. Kazazi (Technical Chamber of Greece, 2006), pp 128–134.

  59. C. Vlachou-Mogire, G. McDonnell, R. Janaway in 4th Symposium on Archaeometry of the Hellenic Society of Archaeometry, vol. 1746, ed. by Y. Facorellis, N. Zacharias, K. Polikreti (BAR International Series, 2008), pp. 545–554.

  60. C. Vlachou-Mogire, B. Stern, G. McDonell, The application of LA-ICP-MS in the examination of the thin plating layers found in late Roman coins. Nucl. Inst. Methods Phys. Res. B. 265, 558–568 (2007)

    Article  CAS  Google Scholar 

  61. C. Vlachou, G. McDonnell, R. Janaway, The Experimental Investigation of Silvering in Late Roman Coinage, in Materials Issues in Art and Archaeology VI. ed. by P.B. Vandiver, M. Goodway, J.L. Mass (II9.2.1-9 Materials Research Society, Boston, 2002)

    Google Scholar 

  62. C. Vlachou, G. McDonnell, R. Janaway, B. Stern, Early Materials Forum London (2001).

  63. D.A. Scott, Metallography and Microstructure of Ancient and Historic Metals (The Getty Conservation Institute, Manna del Rey, 1991)

    Google Scholar 

  64. G. Abbas Gohar, T. Manzoor, A.N. Shah, Investigation of thermal and mechanical properties of Cu–Al alloys with silver addition prepared by powder metallurgy. J. Alloys Compd. 735, 802–812 (2018)

    Article  CAS  Google Scholar 

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This work was part of the author’s doctorate research The manufacturing and plating technology used in the production of mid-3rd/4th century AD Roman coins – An analytical study, submitted to the Archaeological Science Department, University of Bradford, 2004 . The author is grateful to her PhD supervisor Dr Gerry McDonnell for his wealth of knowledge on ancient metallurgy and the valuable guidance, comments and encouragement he generously provided during the project and beyond. The author would like also to acknowledge the Hellenic Republic, State Scholarship's Foundation (S.S.F.) for funding this research project and the British Museum Department of Coins and Medals and Department of Scientific Research, for allowing access to Cope's Archive. Furthermore, the Department of Earth Sciences, University of Manchester and NERC for the permission to use the electron microprobe facility and Mr. Dave Plant for performing the analyses

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Correspondence to Constantina Vlachou-Mogire.

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This invited article is part of a special topical issue of the journal Metallography, Microstructure, and Analysis on Archaeometallurgy. The issue was organized by Dr. Patricia Carrizo, National Technological University–Mendoza Regional, and Dr. Omid Oudbashi, Art University of Isfahan and The Metropolitan Museum of Art, on behalf of the ASM International Archaeometallurgy Committee.

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Vlachou-Mogire, C. Investigation of the Manufacturing Technology of Complex Copper Alloy Late Roman Coins (240 AD to 395 AD) Using Archaeometallurgy Techniques. Metallogr. Microstruct. Anal. 12, 202–218 (2023).

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