The Life-Spans of Empires

The collapse of empires is exceedingly difficult to understand. The author examined the distribution of imperial lifetimes using a data set that spans more than three millennia and found that it conforms to a memoryless exponential distribution in which the rate of collapse of an empire is independent of its age. Comparing this distribution to similar lifetime distributions of other complex systems-specifically, biological species and corporate firms-the author explores the reasons behind their lifetime distributions and how this approach can yield insights into empires.