Antiquity, Middle Ages, Renaissance… Historical epochs structure our imagination and our ways of understanding the present. If epochs are a central category in human and social sciences, they also play a structuring role in the ordinary experience of social actors, and can lead to political action. Yet, epochs remain an understudied phenomenon. What is an epoch ? How to decide where one starts and ends ? What are we the contemporaries of ? And what are the consequences of periodizing attempts on our relationship to time and history ? This special issue of Tracés is precisely dedicated to these questions. The papers gathered in this special issue enlighten the implications of epoch-making through the study of various topics, such as the birth of capitalism, the historiography of Middle Ages, the place of women in the Renaissance, the critique of present time in 15th and 16th centuries' theater, the Caribbean revolutions at the end of the 18th century, the periodization of international relations, the sense of time in the capitalist epoch, the financial crisis of 2008, or the future epochs depicted by science fiction. Thereby, this special issue shows the multiple ways to conceive an epoch, by studying the conditions of their emergence as well as the epistemological and political implications of their uses.