Panel 5.10 – Ingots of metals


Organiser/Chair:

  • Norbert Hanel (Universität zu Köln)

External Discussant:

  • Alfred M. Hirt (University of Liverpool)

Speakers:

Panel abstract

Indicators of metal trade within the Roman Empire and beyond In the middle of the ‚chain of operations' (chaîne opératoire) in a broader sense, where the various technological, economic, historical and social steps are reflected – starting with mining activities/raw material exploitation and ending with the metal final products – ingots are a welcome archaeological type of find. The preserved or sometimes only documented items are the carriers of different metals and their routes can nowadays often be followed from the smelting sites to craftsmen and consumers within the Roman empire. The ingots themselves offer a wealth of information ranging from the knowledge gained from natural science methods, especially concerning the provenance (lead isotope analysis, trace element analysis, etc.), from the forms of the ingots, the different situations of their discovery and find locations up to the numerous epigraphic elements (moulded and chiseled inscriptions, stamps and graffiti). In the context of this discussion, ingots of important metals (gold, silver, brass, copper, lead, iron) are to be presented for the first time in comparison to the framework conditions of the Imperium Romanum. Can we suppose differences between precious metals (gold, silver) and other metals (copper, lead, iron) during transport? Gold and silver ingots are missing, for example, in the numerous shipwrecks of the Mediterranean sea as well as in the Atlantic. Since the ore deposits spread over different provinces, questions arise about the distribution of the ingots in local, inter-regional and long-distance trade. Not always it was possible to choose low-cost sea transport; fluvial and overland-transport must kept in mind. Ports of trade are important as starting point, intermediate and/or terminal stations. We have to assume a network of different merchants (negotiatores, mercatores) including maritime (Mediterranean navicularii, Channel/North Sea ? moritices) and fluvial shipowners (caudicarii, nautae). Even transport of lead to India is attested by ancient authors (Plin. 34, 163; peripl. M. Erythr. 49; 56). Last but not least: How can we reconstruct a widespread distribution of metals within the Roman Empire apart from the main routes of trade?

 

Paper abstracts

1. Rainer Wiegels (Universität Osnabrück/Buchenbach)

Some remarks on the gold- and silver bars of the Late Roman period
Die Verarbeitung von Gold u. Silber zu Schmuckstücken, Prunkwaren oder in der Münzprägung gehörte in der Antike zu den alltäglichen Vorgängen, aus denen gleichermaßen Privatpersonen wie der Staat Nutzen zogen. Zur Beschaffung des Rohmaterials diente auch die Ausbeutung entsprechender Lagerstätten, woran der röm. Staat auf verschiedene Weise beteiligt war, wie das Einschmelzen von Gebrauchsobjekten. Auf dem Weg zu den entsprechenden Schmieden spielten Gold- u. Silberbarren eine zentrale Rolle. Während in der privaten Nutzung Edelmetallbarren in unterschiedlicher Form Verwendung fanden und vor allem bereits verarbeitetes Silber als „Hacksilber“ gehortet oder auch zum weiteren Gebrauch vorgesehen war, nutzte der Staat das kostbare Metall auf verschiedene Weise zu eigenen Zwecken. Dies gilt nicht nur für die staatliche Münzprägung, sondern auch für ganz unterschiedliche Formen von ‚Entlohnungen‘. Dazu zählen etwa prunk- und kunstvoll gestaltete Ehrengeschenke oder auch die in mehr oder weniger roher Form als Subsidien gezahlten Leistungen gegenüber Machthabern im Vorfeld des Reichs. Als eine Besonderheit der Spätantike fällt auf, dass der Sold an Soldaten bisweilen nicht nur in Münzgeld, sondern auch in Barrenform ausgezahlt wurde. Bemerkenswert sind in diesem Zusammenhang besonders gestempelte oder andersartig signierte Barren. Dass angesichts des hohen Verkehrswertes von Barren die speziell gekennzeichneten zu den besonders raren Fundstücken gehören, kann nicht überraschen.

 

2. Sabine Klein (Deutsches Bergbau-Museum Bochum)

Submerged Witnesses of the Past: Roman Copper Ingots from the Mediterranean Sea
Copper metal became particularly important in the Roman Empire, since it was processed on industrial scale and by standardized metallurgical procedures. For archaeometallurgical aspects, copper ingots are the most important link in the sequence from copper ore to metal product. The studied copper ingots belong predominantly to cargoes of ship wrecks from the South coast of France, Corse and Cadiz. They were sampled by drilling, so that the gained material could be used repeatedly for several analysis methods, and is still not consumed. Bulk chemical composition with WD-electron microprobe, microstructural evaluation and the lead isotope composition with a multicollector mass spectrometer at Goethe-University Frankfurt was performed. The presentation shall give an overview of the occurrence of ingots, composition and finesse of the traded copper metal as well as the raw material provenancing towards the mineral sources, which were exploited for the production of the Roman copper ingots.

References:
Jézégu, M.-P. et al., 2011, Nesta, A. et al., 2011, Klein, S. et al., 2007, Rico, Chr. et al., 2005-2006.

 

3. Michael Bode (Deutsches Bergbau-Museum Bochum) / Norbert Hanel (Universität Bochum)

Brass trade in the Roman Empire - a lead isotope study on Roman brass ingots from Corsica
In Roman time, coins, vessels, weapons, fibulae or metal plates for instance have been made to some extent of brass. Increased demand is particularly visible with the introduction of brass coins by Augustus and leads to the question about the origin of the raw materials copper and zinc. Most promising tool for the provenance of metals still is the lead isotope comparison, which in case of brass reflects the lead composition in the zinc component. Zinc is mostly present as calamine, which is closely related to lead minerals. Lead-zinc ores are located in Roman mining districts e.g. on Sardinia, in Germany, Britain, the Cevennes mountains in South France or the south-western Alps. With 21 brass ingots in a shipwreck off the east coast of Aléria (Corsica) an absolute outstanding find has been made in 1980. It can not only be dated very precisely into the end of the 2nd century AD, but also bears the chance to trace back the zinc’s origin as ingots are as far as known not of mixed metal sources. Roman brass workshops are known from France as well as from Germany and Britain, but on the other hand Roman calamine exploitation in the provinces nowhere can safely be located so far. Although with the lead isotope method it is possible to clearly exclude German and Sardinian ores, a further limitation becomes more difficult as lead isotope data overlap. With this paper we like to present all relevant analytical and archaeological information and hand it over for a discussion.

 

4. Peter Rothenhöfer (DAI, Kommission für Alte Geschichte und Epigraphik München) / Norbert Hanel (Universität Bochum)

Lead Ingots and Roman Mining Activities on the Balkans
A detailed study of the Roman lead ingots from the Balkans, of their epigraphic elements together with lead isotope analysis, revealed new insights into Roman mining activities. Many of the previous views and concepts concerning e.g. mining areas and provenances must be revised, and new data - for instance concerning a metallum Messallini - can be added.
The chronological framework starts with the ingots from the Comacchio wreck (c. 35/30-12 BC) and ends with an 4th century ingot recovered at the legionary fortress of Novae/Shvistov.

 

5. Christian Rico (University of Toulouse, TRACES)

Iron Trade in the Early Roman Empire: the case study of Gallia Narbonensis
The talk will propose an overwiew of the Roman iron trade in Western Mediterranean sea, specially off South Gaul coasts, illustrated by several shipwrecks found near Saintes-Maries-de-la-Mer and the Rhône mouth. Archaeological and epigraphical data, combined with physics, allow us to characterize the trade in its volume and its duration, and to understand its organization. The aim of the study is to replace the iron trade in the whole metal trade in Western Medtierranean sea during the Early Roman Empire.