Rome and the Coinages of the Mediterranean: 200 BCE to 64 CE

Project Information

RACOM

Grant agreement ID: 835180

DOI

10.3030/835180

Project closed

EC signature date 20 May 2019

Start date 1 September 2019

End date 31 August 2025

Funded under

• EXCELLENT SCIENCE - European Research Council (ERC)

Total cost

€ 2 484 832,00

EU contribution

€ 2 484 832,00

Coordinated by

UNIVERSITY OF WARWICK
United Kingdom

Periodic Reporting for period 4 - RACOM (Rome and the Coinages of the Mediterranean: 200 BCE to 64 CE)

Reporting period: 2024-03-01 to 2025-08-31

Summary of the context and overall objectives of the project

Ancient silver coinage formed the backbone of state finance in antiquity. The fineness of a coinage is often taken by historians to be a comment on the fiscal health of the issuing state, yet until now very little has really been known about its fineness and chemical composition. Many previous analyses were inadequate to answer key questions, because the samples for analysis were taken from the surfaces, or from just beneath the surfaces, of silver coins, and these are not representative of the original alloys used. The RACOM Project adopted a sampling method to overcome this problem, resulting in a large dataset of reliable analytical results for the composition of these coinages.

The historical period covered by the RACOM Project, from c. 150 BCE to 64 CE, is important in the economic development of the Mediterranean world. It witnessed a major increase in long distance trade and probably also economic growth and a rise in per capita income. Flows of precious metals to Rome and other important centres of power helped finance Roman expansion. It is generally thought that greater monetary integration of the Mediterranean accompanied Roman conquests; however, the continuation of local and regional silver coinages of traditional type challenges the idea of the spread of Roman coinage as an instrument of imperialism.

The objective has been to examine financial and monetary strategies during that time through detailed analyses of the chemical composition of all major silver coinages of the period, taking samples from deep within the coins (where the original 'recipe' used for the coinage alloy is preserved). The samples are then analysed by two complementary, well-established techniques (microwave-plasma atomic emission spectrometry; and inductively-coupled plasma mass spectrometry).

Taking drilled samples from museum coins is not always possible, and the project has also evaluated two new, minimally destructive, or non-destructive, techniques to see how they compare with established protocols: muon x-ray emission spectroscopy; and laser ablation inductively-coupled mass spectrometry.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

The Project comprised two main work packages, both successfully completed: one (Work Package A) involving the sampling and analysis of coins using standard protocols, together with studies of metrology and circulation patterns; and the other (Work Package B) evaluating two relatively new sampling techniques: laser ablation; and analysis using negative muons. A third package (C) covered Open Access dissemination of the work.

A database was developed to house the full numismatic data on each coin (including images) along with its compositional data (a suite of 14 elements for all coins). This is publicly available on the Archaeology Data Service (ADS).

The selection and sampling of coins was undertaken in major museums in the UK, the USA, Europe and Israel, resulting in a dataset of 2,942 coins (including some legacy data). Two hundred samples were selected for lead isotope analysis. For the 1,202 Republican coins the coverage is particularly full. In the case of the Hellenistic coinages, many of these have never been analysed before. The geographical coverage is comprehensive, including specimens of most mints issuing silver coins in the eastern Mediterranean. We now have a good data set of robust analytical data of silver coinage of the Mediterranean for the entire period from the mid second century BCE to the reforms of Nero in c. 64 CE. This informs the monograph by the PI and Dr Ponting.

The Work Package B experiments highlighted some challenges for the muon and laser sampling when analysing debased coins. The problems with both techniques are particularly apparent when analysing coins of 33% fine or less.

Two project conferences were held: in Liverpool (April 2022); and in Rome (April 2023). Both are being published by the Royal Numismatic Society. Videos of papers presented at the RACOM Rome conference are hosted on the RACOM web page.

A public exhibition about the project mounted by the RACOM team has been housed at the University of Warwick since June 2025. The project attracted media interest, which was reported on by news outlets around the world.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The RACOM Project has generated the largest and most comprehensive set of analyses of Roman Republican and late Hellenistic Greek silver coinages ever. Previously all that existed were analyses of small groups of coins, using a variety of sampling strategies and analytical techniques, and one comprehensive study of Republican coins using a faulty sampling strategy that reported on silver content only. These results vastly surpass all previous studies and provide robust and reliable results for the scholarly community to use for study.

The Project has also used analytical data to highlight the importance of recycling of old metal stocks as a key source of raw materials for new coinages. This is in contrast to many studies that have sought to identify the geological sources (the mines) from which the silver came; we believe that the evidence shows that coinage is not well-suited to that type of investigation because the materials were continuously recycled. The operational chains within a mint had a major influence on the trace element signature of the coinage it produced. Thus the compositional signatures produced by the analyses tend to be those of the mints, not the mines. This new approach places an emphasis on working traditions and understanding how the systems processed the material rather than privileging the geological origins.

From the middle of the second century BCE there was a tendency towards progressive debasement of Hellenistic coinages, and the RACOM data provide a detailed account of the chronology of these changes. It is now possible to compare the quality of coinages of different states with one another, something that was entirely impossible before RACOM. Comparing contemporary issues of different states not only allows us to highlight differences between them, but also allows us to see cases where stocks of metal may have been pooled.

Metrological work shows that corrosion has had a major effect on the weights of many silver/copper alloy coins in museums, so that they do not preserve the original weight standard. The RACOM Project has advanced a method for rectifying this problem.

The study of coin circulation highlights the limited penetration of the Roman denarius in the eastern Mediterranean for most of the period covered by the RACOM Project. While Roman coinage clearly influenced the issues of the western Mediterranean and came to eclipse local issues there, it is more difficult to make the case for this in the east. Formal integration seems to come only in the reign of Augustus (27 BCE - 14 CE), and even then it appears to have been a hybrid system rather than full 'Romanisation'.

In evaluating the two new techniques, laser ablation and muon XES, the RACOM Project has highlighted issues that arise when analysing debased coins using these methods, and ways that these can be overcome.

The results of the RACOM Project fulfil an important need among historians of the ancient economy for a set of reliable analyses of ancient silver coins, and provides a road map for the investigation of silver coinages of other periods. The implications of the new data are so wide-ranging that they will have an impact far beyond the lifetime of the RACOM Grant itself.

Detail of the edge of a Roman denarius in Yale University Art Gallery showing size of sample hole.

Dr Matthew Ponting takes a drilled sample from a Roman denarius in the Firestone Library, Princeton.