In modern scholarship, Christianity and the classical city, which constitues the original founding element of Greco-Roman civilization,1 are often deemed to be incompatible. The communis opinio may be summarized in Mogens Hansen's assertion that the polis, with its polytheistic cults and events, was a Pagan institution in which worthy Christians could take no part.2 More generally, Voltaire's idea3 of a causal relationship between two distinct historical phenomena, viz. the conversion to Christianity and the end of the Ancient World, prevails in a signifijicant number of studies of Late Antiquity.4 The confusion encourages one to reassess the relationships between those two key events. This volume, which results from the conference on "Religious Practices and Christianization of the Late Antique City" held at the Université libre de Bruxelles from January 19 to 21, 2012, seeks to study the phenomenon of the Christianization of the Roman Empire within the context of the transformations and eventual decline of the Greco-Roman city. The studies brought together here aim to describe with greater precision the possible links between religious, but also political, economic and social mutations engendered by Christianity and the evolution of the antique city. More particularly, an efffort will be made to measure the impact on the city of the progressive abandonment of traditional cults to the advantage of new Christian religious practices. The papers in this volume will cast a new light on the intersection between the Christianization of the Roman Empire and the progressive disappearance of the municipal civilization characteristic of Greco-Roman Antiquity. It is hoped that this Introduction, though not intended to offfer an exhaustive 5 Cf. the terminological analysis in Inglebert (2010) 9. 6 Cf. the historiographical assessment established in Inglebert (2010).