Abstract
Since 2000, advances in the natural sciences have led to increasingly precise knowledge of the climate and its spatial and temporal variations in Roman times. The question of the role of these variations in Roman history was quickly raised in terms of opportunity, constraints and even crisis. Discussions focused in particular on the " Roman optimum " and its end, on the transformations of late antiquity, and also on the Republican era. Discussions have focused on both the long term, in connection with demographic and economic issues, and the short term, in connection with episodes of volcanic forcing such as the Okmok in 44 BC, those of the Antonine period and the considerable changes of the Justinian era. We propose a tentative assessment - necessarily provisional - of our knowledge and, above all, of the questions and methodological issues that are currently being addressed : under what conditions can climate be used as a historical operator in the Roman Empire ?
