Abstract: The 160's BCE was the critical decade in Ptolemaic history, marking the beginning of serious state decline. The causes of this decline have often been attributed to internal problems, depravity of the kings themselves, and the increasing political and military domination of the Mediterranean by Rome. Environmental factors have never been considered until now in the understanding of social dynamics, or in the economic, military and fiscal history of the dynasty. A new chronology of volcanic eruptions from polar ice core analysis affords us an opportunity to reevaluate historical dynamics within Egypt, to examine more critically how shocks to the annual Nile flood may or may not have played a role in "decline" and social unrest. Ice cores also allow us to tie events in Egypt to those across the Indian Ocean in the same years.

Joseph Manning is a Professor in both the Classics and the History Departments at Yale, and a Senior Research Scholar at Yale Law School.He specializes in Hellenistic history with particular focus on the legal and economic history of Ptolemaic Egypt. Joe’s current research is situated at the intersection of paleoclimatology and the economic history of the premodern world. He is part of a small team that has been working on understanding the impacts of explosive volcanic eruptions on the Nile watershed. Before coming to Yale, he taught for 12 years at Stanford University and two years at Princeton University.