Buried Coins Speak Of Population Declines in Ancient Rome

Buried Roman coins that citizens hid to protect their savings in times of instability, indicate that during the 1st century B.C the population of ancient Rome was smaller than sometimes suggested.

The approximate population size of the late Roman Republic in the first century B.C., a time that marked the assassination of Julius Caesar and the fall of the Roman Republic, remain the subject of intense debate.

Depending on who historians believe was counted in the early Imperial censuses (adult males or the entire citizenry including women and children), the Italian population either declined or more than doubled during that period.

In an article published online in the Proceedings of the National Academy of Sciences, University of Connecticut theoretical biologist Peter Turchin and Stanford University ancient historian Walter Scheidel attempt to answer the population question by mapping out the times when the coins were buried.

"In times of violence, people tend to hide their valuables, which are later recovered unless the owners had been killed or driven away. Thus, the temporal distribution of unrecovered coin hoards is an excellent proxy for the intensity of internal warfare," the researchers wrote.

Basically, more stashes means a dropping population, due to the greater frequency of violence.

Turchin and Scheidel developed their mathematical model using census data of the period before 100 BC, when Roman population history is relatively uncontroversial.

Indeed, the model’s trajectory successfully captured major demographic trends during that period, including the short-lived population increase before the Second Punic War, demographic contraction during the war, and sustained population growth in the second century BC.

The researchers then tested the model using coin hoard data after 100 BC, and found that the trajectory mirrored a declining population.

"Judging by the number of hoards found during the first century BC, this period was as calamitous as the war with Hannibal. Actually it was even worse, because there was not just one, but two large clumps of hoards. It is very difficult to imagine how a population could grow during a period of such violence, and the model provides a precise quantitative statement of this," Turchin said in a statement.