The digitisation of archaeological collections is transforming the study of ancient history. By combining millions of records with spatial analysis and quantitative methods, researchers can now uncover economic patterns that would be difficult to detect from individual artefacts. A new study of Roman coins demonstrates how this data-driven approach can reveal the economic forces behind Rome’s expansion.
Researchers Eduardo Amaral Haddad and Inácio Fernandes Araújo of the University of São Paulo analysed approximately four million coins dating from 155 BCE to 2 CE. Published in Humanities and Social Sciences Communications, the study suggests that while military conquest initiated Roman expansion, lasting control depended on the economic integration of conquered territories.
Each archaeological coin provides information about where and when it was minted and where it was eventually discovered. Individually, these details reveal relatively little. Analysed collectively, however, millions of coins can trace monetary movement, economic exchange and connections between regions. The researchers examined about four million coins organised into 24,646 hoards and 5,167 pairs of minting and discovery locations.
The team combined several large archaeological databases with geographic information systems and techniques commonly used in regional economics. These resources provided information about coin hoards as well as Roman cities, roads, ports, rivers and sea routes. The researchers then applied mathematical methods normally used to study modern movements of people, goods and income to reconstruct monetary circulation across the ancient Mediterranean.
Their analysis showed that Roman coins were not distributed randomly. Instead, they formed significant clusters along major trade and transportation routes. Coins originating in Rome spread through networks of roads, ports and urban centres, indicating that infrastructure played a crucial role in connecting newly acquired territories with the Roman economic system.
The researchers also developed a model of the Roman economy incorporating relationships among government, households, landowners, merchants, enslaved people and the army. This helped them examine the gradual monetisation of Roman society, as transactions that had once been conducted partly through goods increasingly shifted towards payments using coins.
The findings suggest that the Roman army was particularly important during the early stages of expansion. Soldiers and military suppliers introduced greater monetary circulation into newly conquered regions. But military activity alone did not sustain it. As territories became permanently incorporated, markets, cities, administrative institutions, religious centres and civic structures generated continuing demand for currency. Military expenditure gradually gave way to civilian, administrative and commercial activity.
The researchers also found that coins travelled increasingly farther from their places of origin as Rome expanded. The influence of geographical distance on monetary circulation progressively weakened, suggesting that previously separated regions were becoming connected through common transportation, markets and institutions. The findings indicate that Rome’s long-term strength rested not simply on conquest, but on its ability to transform conquered territories into parts of an increasingly integrated economy.
More information: Eduardo Amaral Haddad et al, Economic footprints: mapping coin circulation and economic networks in ancient Rome, Humanities and Social Sciences Communications. DOI: 10.1057/s41599-026-07815-7
Journal information: Humanities and Social Sciences Communications Provided by Fundação de Amparo à Pesquisa do Estado de São Paulo