The aim of this paper is to provide the historical research on both religion and the city with a serviceable analytical distinction between 'urbanisation' and 'citification' as two sets of socio-spatial phenomena related to the role of religion in city-spaces. Inspired by modern social and political theory, the notion of 'citification' has been crafted with the purpose to be tested on early Christ religion in order to better foreground its character of an 'urban religion'. The paper ends by suggesting how the concept of 'citification' can be profitably applied to the historical study of other ancient constellations of religiously infused spatial practices in interaction with the urban space. Focus, applied concepts and methods Testing 'Urban Religion' on past cities and ancient religions*1 The path to the study of urban religion has to be cleared. The urban world, […], is alive with the competing and divergent dreams projected onto it and found within it by outsiders. It is crisscrossed by discrepant narratives and fissured by incommensurable visions of what is possible and good in cities. Before we look at cases of religious engagement with the urban world, then, we have to step back and examine what converges on that world ; to see what Moishe Sacks, Mama Lola, and the other religious improvisors who appear in this collection of essays made of the city for themselves, we have to consider first the broad outlines of what was being made of the city for and against them, in the plans and programs of others (Orsi 1999a: 12; emphasis mine). These lines are taken from Robert Orsi's introductory chapter of Gods of the City (Orsi 1999a), the collective volume on lived religion in contemporary American cities that, more twenty years ago, sparked the study of 'urban religion' (Garbin and Strhan 2017b: 4; see Rüpke 2020: 4-8). The epistemological barriers created by the academic division of labour probably explain why it took almost fifteen years to fully realise that Orsi's agenda, as instantiated by the quotation above, might apply also to past cities and ancient religions: namely, to 'cases of religious engagement with urban world(s)' that are not 'alive' and out there, like in social science ethnographies (e.g., Orsi 1985; Hall 1997; McGuire 2008), but dead and nowhere but in archaeological findings and written records. Indeed, the ERC-funded project on 'Lived Ancient Religion' (LAR) has shown that there always existed 'religious improvisers,' small religious entrepreneurs, and self-styled religious experts among the urban commoners (e.g., Gasparini et al. 2020; Albrecht et al. 2018; for the initial agenda, see Rüpke 2011). An extensive body of cross-temporal and-disciplinary research spanning from Karanis to Palmyra, from Pergamum and Carthage to Pompeii and Rome, the LAR approach has demonstrated that embarking on the search of the ancient Mediterranean 'colleagues' of the creative protagonists of Gods of the City does make sense. Rather, the unaccomplished task is to foreground the 'spatiality' of these ancient loc...