{"pk":53812,"title":"On the Life Cycle of Empires","subtitle":null,"abstract":"<p>We provide empirical evidence that the distribution of empires' lifetime is exponential with a typical time-scale of 300 years. After introducing and computing a proxy measure for the dimension of a large polity we interpret the data by means of a simple dynamical model for the empires' evolution. The resulting theory suggests that the behavior of a long-lived empire is qualitatively different from a short-lived one. They all experience an initial expansion phase but while the former goes through a contraction period over the last $20\\%$ of its life, the latter stays essentially unchanged after reaching its maximum size. In both cases, a sudden collapse occurs when the empire's size is still close to its own historical average.</p>","language":"eng","license":{"name":"Creative Commons Attribution 4.0","short_name":"CC BY 4.0","text":"Attribution — You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.\n\nNo additional restrictions — You may not apply legal terms or technological measures that legally restrict others from doing anything the license permits.","url":"https://creativecommons.org/licenses/by/4.0"},"keywords":[{"word":"Empires"},{"word":"Life cycle"},{"word":"Collapse"},{"word":"World History"},{"word":"civilizations"}],"section":"Article","is_remote":true,"remote_url":"https://escholarship.org/uc/item/8p0176zr","frozenauthors":[{"first_name":"Stefano","middle_name":"","last_name":"Ciliberti","name_suffix":"","institution":"Paris Sciences Lettres","department":"EPHE"}],"date_submitted":"2025-10-31T16:53:34.124000Z","date_accepted":"2025-11-20T13:01:33.241000Z","date_published":"2025-12-25T11:54:00Z","render_galley":{"label":"PDF_final","type":"pdf","path":"https://journalpub.escholarship.org/cliodynamics/article/53812/galley/48732/download/"},"galleys":[{"label":"Manuscript_final","type":"other","path":"https://journalpub.escholarship.org/cliodynamics/article/53812/galley/48731/download/"},{"label":"PDF_final","type":"pdf","path":"https://journalpub.escholarship.org/cliodynamics/article/53812/galley/48732/download/"}]}