Copper-based alloys of the fifth century - article ; n°34 ; vol.6, pg 54-76

C.E. King, J.P. Northover, D.M. Metcalf

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Revue numismatique - Année 1992 - Volume 6 - Numéro 34 - Pages 54-76
Summary. — This paper is a preliminary investigation of the alloy content of late Roman, Vandalic, and Ostrogothic bronze coins (analysed by electron microprobe) minted in the fifth and sixth centuries A.D. The results show that tin contents were significantly higher in the West in coins of Rome and Carthage while eastern and Ostrogothic nummi (and post-reform pentanummia) were composed of a poor quality copper alloy with high lead contents. Larger denominations minted after the Anasta- sian reform and by the Vandals, on the other hand, are almost pure copper.
23 pages
Source : Persée ; Ministère de la jeunesse, de l’éducation nationale et de la recherche, Direction de l’enseignement supérieur, Sous-direction des bibliothèques et de la documentation.

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• Publié par: REVUE_NUMISMATIQUE
• Publié le: 01 janvier 1992
• Nombre de lectures: 14
• Langue: English
• Poids de l'ouvrage: 2 Mo

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C.E. King
D. M. Metcalf
J.P. Northover
Copper-based alloys of the fifth century
In: Revue numismatique, 6e série - Tome 34, année 1992 pp. 54-76.
Abstract
Summary. — This paper is a preliminary investigation of the alloy content of late Roman, Vandalic, and Ostrogothic bronze coins
(analysed by electron microprobe) minted in the fifth and sixth centuries A.D. The results show that tin contents were significantly
higher in the West in coins of Rome and Carthage while eastern and Ostrogothic nummi (and post-reform pentanummia) were
composed of a poor quality copper alloy with high lead contents. Larger denominations minted after the Anasta- sian reform and
by the Vandals, on the other hand, are almost pure copper.
Citer ce document / Cite this document :
King C.E., Metcalf D. M., Northover J.P. Copper-based alloys of the fifth century. In: Revue numismatique, 6e série - Tome 34,
année 1992 pp. 54-76.
doi : 10.3406/numi.1992.1974
http://www.persee.fr/web/revues/home/prescript/article/numi_0484-8942_1992_num_6_34_1974С. Е. KING*, D. M. METCALF*, J. P. NORTHOVER*
COPPER-BASED ALLOYS OF
THE FIFTH CENTURY.
A COMPARISON OF CARTHAGE UNDER
VANDALIC RULE, WITH OTHER MINTS
(PL XI-XIII)
Summary. — This paper is a preliminary investigation of the alloy content of late
Roman, Vandalic, and Ostrogothic bronze coins (analysed by electron microprobe)
minted in the fifth and sixth centuries A.D. The results show that tin contents were
significantly higher in the West in coins of Rome and Carthage while eastern and
Ostrogothic nummi (and post-reform pentanummia) were composed of a poor quality
copper alloy with high lead contents. Larger denominations minted after the Anasta-
sian reform and by the Vandals, on the other hand, are almost pure copper.
Résumé. — Une première enquête sur la composition des monnaies de bronze romano-
byzantines des ve-vie siècles, à partir d'analyses pratiquées à Oxford par « Electron-
Microprobe » révèle deux différences significatives. D'une part l'étain est toujours plus
élevé en Occident (Rome ou Carthage) qu'en Orient où il ne dépasse jamais 5%.
D'autre part, tant en Orient qu'en Occident les petites unités (pentanoummia ou
moins) sont en bronze pauvre à forte teneur en plomb, tandis que les dénominations
plus élevées (vandales « autonomes », folles d'Anastase Г série) sont en cuivre quasi pur.
'argentiferous' bronze coinages of the Research into the alloy of the
third and fourth century has shown that the proportions of different
metals (most noticeably copper, tin, and lead) differed between mints and
sometimes at the same mint between different issues. The same is true of
the Byzantine coinages which we commonly refer to as 'copper'.
* Heberden Coin Room, Ashmolean Museum, Oxford 0X1 2PH
Revue Numismatique, 1992, 6e série, XXXIV, p. 54-76. COPPER-BASED ALLOYS AD 395-530 55
Studies exist of the metal contents of Byzantine coinages of the sixth
century from the full range of mints, namely Constantinople through
Antioch, Alexandria, and Carthage, to Rome and the other Italian
mints. Grierson in 1965 published semi-quantitative data on trace el
ements in Byzantine coins, x and his results were supplemented by Butler
and Metcalf in 1967. 2 Padfield in an important paper in 1972 published
quantitative EPMA results for 8 elements, using XRF analyses as a
control, for 84 carefully selected coins of the sixth and seventh centuries
which included some from virtually every mint. 3 While recognizing that
half a dozen specimens from a particular mint was a totally inadequate
sample from which to determine mint-policy and practice for a period of
approximately 200 years, Padfield was nevertheless able to present 18
tentative but useful conclusions. Among the more important was his
recognition of a difference in alloy between eastern and western mints.
Eastern coinages from the mints of Constantinople, Nicomedia, Cyzicus,
and Antioch, with the exception of pentanummia of Constantinople and
Nicomedia, were made essentially of copper. Coins of the African and
western mints were made of a leaded low-tin bronze, generally containing
around 3 per cent tin.
Padfield did not analyse any Vandalic coins, and we thought it would
be of interest to supplement his survey by discovering whether the wes
tern tradition pre-dated the Byzantine conquest of Carthage. This ambit
ion was frustrated by the lack of sufficient material of such an early
date. The first issues of nummi at Carthage appear to have been in the
time of Gunthamund (484-496). Wroth's catalogue classes as Vandalic
various types which should now be transferred elsewhere, and he misdat
es others. Our analyses show that the Vandalic folles and their fractions
were made of a bronze alloy, with the second series, in particular, nor
mally containing c. 7 per cent tin. In some cases this bronze was leaded,
and occasionally specimens contain extraordinarily high amounts of lead
but very little tin. (figs. 1-2). Wroth, long ago, attributed these folles to
Geiseric (428-477) and Huniric (477-484) respectively, thus before the
Anastasian reform. The character and dating of the two series have been
much debated, by Grierson, Morrisson, Hahn, and others, who are agreed
in pushing them forward to more recent dates — and in seeing them as in
1. P. Grierson, Trace elements in Byzantine copper coins of the 6th and 7th centur
ies, in Dona Numismatica, Walter Hávernick zum 23. Januar 1965 dargebracht, Hamb
urg, 1965, p. 29-35.
2. В. С M. Butler and D. M. Metcalf, Trace elements in Byzantine copper coins :
a method of non-destructive analysis, NCirc, 75, 1967, p. 229-33.
3. T. Padfield, Analysis of Byzantine copper coins by X-ray methods, in Methods
of Chemical and Metallurgical Investigation, (eds. E. T. Hall, D. M. Metcalf), London,
1972, p. 219-34. 56 С. Е. KING, D. M. METCALF, J. P. NORTHOVER
some sense 'municipal' rather than royal coinages. 4 Their exact chronol
ogy, however, remains debateable. It is very unlikely that they begin
earlier than c. 480, and Hahn places their introduction in the sixth cen
tury. Thus it is unclear whether they began before or after the Anasta-
sian reform.
We are in no position, therefore, to ask whether the alloy of the Vanda-
lic coins was or was not influenced by the Anastasian reform, and in any
case we ought rather to be asking whether they were influenced by Ostro-
gothic foundry practice since it is clear that they closely follow Ostrogo-
thic precedent in other respects.
We were also interested to consider whether a similar variability of tin
and lead contents occurred in the fifth century, before the Anastasian
reform, at other mints, and whether it was a chance occurrence or whe
ther specific alloy proportions were intended by individual mints. The
coins of Arcadius and Zeno studied by Bibra, which were the only analys
es available for the fifth century, had copper contents in excess of 96 per
cent, low tin and lead contents and surprisingly high zinc contents (0.9 to
1.8 per cent). Unfortunately their mints are not recorded.5
We also wondered whether we could distinguish signs of the melting
down of older Roman issues to supply metal for reminting as Vandalic
'copper' coins. This arose out of the examination by one of us of crucibles
currently being studied in the Department of Materials, University of
Oxford (for future publication) which had been found on a site in the Rue
Septimě Severe by the British team excavating in Carthage in 1987 in a
context which probably belongs in the period of the Vandalic occupat
ion. The crucibles had been used to melt bronze alloys containing up to
2 per cent silver and their compositions resemble some of the most deba
sed third century Roman issues of the 260s to the early 280s. Given the
fact that the alloy of very debased issues of argentiferous bronzes of the
third and fourth centuries often had no more than c. 1 to 3 per cent silver
in its composition, this seemed a possible explanation for the occurrence
of the silver in the alloy in the crucibles. Unfortunately, correspondingly
complete analyses are not available for the last years of the third century
4. P. Grierson, The "tablettes Albertini " and the value of the solidus in the fifth
and sixth centuries A.D., JRS, 49, 1959, p. 73-80; C. Morrisson, Les origines du
monnayage vandale, in Actes du 8e Congrès International de Numismatique, 1973, Paris-
Basel, 1976, p. 416-72; id., The re-use of obsolete coins: the case of Roman imperial
bronzes revived in the late fifth century, in Studies in Numismatic Method presented to
Philip Grierson, ed. С N. L. Brooke et al., Cambridge, 1983, p. 95-111 ; W. Hahn, M IB
vol.3, Vienna, 1981, p. 58-63; P. Grierson and M. Blackburn, MEC, vol. 1, Camb
ridge, 1986, p. 21-3 and pi. 1-3.
5. Published in J. Hammer, Der Feingehalt der griechischen und romischen Miinzen,
ZbN, 26, 1908, p. 1-144, and reprinted in Methods of Chemical and Metallurgical Inves
tigation, p. 431 f. COPPER-BASED ALLOYS AD 395-530 57
or for the fourth century and the fail