Identity is a polysemic, politically saturated and even polemical notion. Sometimes considered a formidable problem when it is associated with fundamentalism and extreme nationalism, identity is seen at other times as a precious asset, a project to be built or a treasure to be regained, for example when it is a question of a European identity. However, the term identity remains difficult to replace. The many phenomena it evokes are nothing less than existential, for individuals and groups, in that they refer to the questions ‘Who am I?’, ‘Who are we?’ and ‘Who are they?’, as Charles Tilly pointed out. By focusing more on processes of identification than on given identities, historical sociology reveals the relational and changing character ...