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Edited by Charles S. Spencer, American Museum of Natural History, New York, NY, and approved August 31, 2009 (received for review April 28, 2009)
Abstract
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. We use this relationship to resolve a long-standing controversy in Roman history. Depending on who was counted in the early Imperial censuses (adult males or the entire citizenry including women and minors), the Roman citizen population of Italy either declined, or more than doubled, during the first century BCE. This period was characterized by a series of civil wars, and historical evidence indicates that high levels of sociopolitical instability are associated with demographic contractions. We fitted a simple model quantifying the effect of instability (proxied by hoard frequency) on population dynamics to the data before 100 BCE. The model predicts declining population after 100 BCE. This suggests that the vigorous growth scenario is highly implausible.
Footnotes
- 1To whom correspondence should be addressed. E-mail: peter.turchin{at}uconn.edu
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Author contributions: P.T. and W.S. designed research; P.T. and W.S. performed research; P.T. analyzed data; and P.T. and W.S. wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission.
Coin hoards speak of population declines in Ancient Rome
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