During the first century BC, Rome experienced a series of civil wars. Dynasts like Marius, Sulla, Caesar, Antony, and Octavian led armies that slaughtered foreigners and Romans alike. Romans responded to these wars by hoarding their wealth. They hoarded some of this wealth by burying coins. Not all of the first-century Romans who buried coins had a chance to dig their coins up again. Some of the coins they buried have come to light only in recent centuries. Scholars study these newly recovered coins to learn about life in ancient times.
Historian Walter Scheidel and biologist Peter Turchin have looked at some of these recently uncovered first-century BC hoards of coins in Rome. Using analytic techniques developed by biologists, Scheidel and Turchin have concluded that the population of Rome in those days was considerably smaller than has often been estimated. The civil wars evidently took so heavy a toll on the Romans that the city’s population by the end of the first century was not likely more than half of the number some previous historians have estimated.