摘要:Forged within the multifaceted forces of social interaction, collectivities come in a bewildering variety of configurations. They may take form for different reasons, they may be made up of people whose adherence to the group varies depending on a further host of factors. This contextual nature of social groupings makes collective identity a difficult matter to study and define in a historical perspective. This collection's aim is to offer a summary of these issues. Starting from a seminar held in Naples (Federico II University, February 11, 2014), organized in the context of FIRB Research Project entitled “The Construction of Space and Time in the Transmission of Collective Identities. Religious Polarizations and/or Cohabitations in Ancient World (1th-6th cent. CE)”, the articles included in this monographic section organize their specific analysis into a more general key component: collective identity as the perception of similarities and differences, so, more generally, communal identity as a social process. Such a general depiction of group identity serves as the basis for the examination of identity-formations, also of the so-called “religious” identities, according the perspective of longue durée as it emerges in more recent researches.