Periodizations are a fundamental element of historical thinking, and for this reason are a matter of importance for all historians. And yet, the history of periodization as such has only rarely been interrogated. Zeitenwende aims to address this shortcoming by engaging with some of the principal themes and problems in the historical study of periodization across different periods, regions, and historiographical traditions. Zeitenwenden begins from the assumption that, far from being neutral or merely technical classifications, historical periodizations are driven by political, cultural, economic, intellectual, and religious agendas in the present day. In other words, they tell us as much about the periodizer as the periodized. Recognizing that the field is of increasing interdisciplinary importance, the volume aims to set an agenda for a new history of periodization.