For centuries, the study of ancient history relied primarily on interpreting classical texts and examining inscriptions and archaeological remains at their sites of origin or in museums. In recent years, however, a little-known transformation has profoundly changed this landscape. The digitization of extensive archaeological collections, coupled with the development of quantitative methods that can integrate millions of scattered records, is ushering in a new era of historical research. Like other scientific disciplines that have benefited from processing colossal amounts of information, archaeology and history have entered the era of data science.
Two researchers from the Regional and Urban Economics Lab at the University of São Paulo (NEREUS-USP) in Brazil have just presented an example of this approach. Using techniques from regional economics, spatial analysis, geographic information systems, and large international archaeological databases, they reconstructed the monetary circulation of the Roman Republic, focusing on the period from 155 BCE to 2 CE, based on the remains of approximately four million coins found in excavations conducted over two centuries. Their study shows that the consolidation of Roman rule depended less on military conquest and more on the economic integration of the territories they conquered.
The research was conducted by Eduardo Amaral Haddad , a professor at the School of Economics, Business, and Accounting (FEA-USP), and Inácio Fernandes Araújo , currently a professor at the Luiz de Queiroz College of Agriculture (ESALQ-USP). The two authors published an article in the journal Humanities and Social Sciences Communications, which is part of the Nature group.
The research seeks to understand how coins reflect the functioning of a growing economy, going beyond simply tracking their movement. "Each coin preserved by archaeology provides three key pieces of information: where it was minted, when it was produced, and where it was found some 2,000 years later. Taken in isolation, that information reveals little. However, when millions of records are analyzed together, they can reveal the paths taken by money, the intensity of economic exchanges, the integration between different regions, and even the institutional evolution of one of the largest economies of antiquity," says Haddad.
The research was supported by FAPESP through two projects ( 14/25030-2 and 19/00057-9 ).
A study that began as a hobby
The project originated in 2014 when Haddad, already a professor at FEA-USP, took a sabbatical at Princeton University in the United States. Although he was conducting research in economics, he began attending a weekly seminar organized by the Department of Classical Studies out of personal interest.
"At one of those meetings, I attended a presentation of a study that used shipwreck remains and pottery shards to reconstruct trade networks in the ancient Mediterranean. That idea stuck with me. Shortly thereafter, while exploring the university library, I found a catalog of Roman coins that contained the information I needed: the date of minting, the location where each coin was produced, and the site where it was found during archaeological excavations. I photocopied the catalog, thinking it would be possible to analyze those networks using tools from regional and urban economics," he recalls.
That initial interest eventually turned into a long-term project. To deepen his knowledge of the classical world, Haddad enrolled in a distance-learning graduate program on the ancient Mediterranean offered by the University of Leicester in the United Kingdom. One of the papers he wrote during the program became the basis for a published article.
Computational archaeology
For a long time, information on Roman coins was scattered among museums, libraries, private collections, and researchers' archives. This fragmentation hindered attempts to reconstruct large-scale circulation patterns. However, the situation began to change when institutions such as the American Numismatic Society started coordinating international projects to digitize and standardize these collections. These projects established common protocols for recording archaeological information. Today, large public databases bring together millions of records from excavations conducted in different countries.
"The main source for our study was Coin Hoards of the Roman Republic Online [ CHRR ], a database dedicated to coin hoards from the Roman Republic. The study also drew on various digital archaeology platforms. Among them was ORBIS , developed by Stanford University [United States], which simulates travel along the network of roads, rivers, and sea routes of the Roman world and estimates the time and cost of journeys between hundreds of locations. The study also included the Pleiades gazetteer and the Roman Road Network databases, which provided georeferenced information on cities, roads, and ports in the ancient Mediterranean," Haddad explains.
These databases were integrated into a single spatial analysis system. After a careful curation process, the researchers began working with a set of approximately four million coins organized into 24,646 hoards corresponding to 5,167 pairs of minting and discovery sites. Rather than analyzing the coins individually, the researchers chose to use these archaeological records, thereby reducing distortions caused by differences in their preservation, loss, or reuse over the centuries.
However, the goal went far beyond simply creating maps. "We needed to consider that circulation from the perspective of human interaction in space according to an economic logic," Haddad explains. It was at that moment that his expertise in regional economics found an unexpected application. The same mathematical tools developed to study contemporary flows of people, goods, and income were used to investigate monetary movements that occurred more than 2,000 years ago. Instead of analyzing modern cities, the focus shifted to the Roman Mediterranean. Instead of tracking contemporary supply chains, the researchers sought to reconstruct the economic networks that sustained Rome's expansion during the last two centuries of the Republic.
