Situating Rome within wider debates on Classical Urbanism is notoriously challenging. It cannot be ignored; the city was the point of reference for a civilization built on urban centres. Rome's resilient power to absorb, adapt and re-present itself underpinned its longevity. Yet while this rightly ensures Rome has a profound significance in discussions of the Classical and Late Antique city, the pulse that sustained the urbs Roma aeterna was also very much its own. No urban centre in the Mediterranean world could match its sustained dynamism, and as Purcell (2007) observed in his discussion of the horti of peri-urban Rome, the drivers that underpinned its evolution were often particular to the circumstances of the city itself. The European Research Council-funded 'Rome Transformed' Project https://research.ncl.ac.uk/rometrans/ (grant agreement No. 835271, Haynes et al. 2020;2021; seeks to understand better this dynamism and its implications, through detailed study of a neighbourhood on the periphery of the Late Republican city, outside Rome's pomerium, which went on to become the centre of western Christendom for a millennium. The project's focus is on the eastern Caelian, and most particularly, on the eight formative centuries that ran from the Principate of Augustus to the Pontificate of Leo III. This paper concentrates on the first four of those centuries.Before proceeding, we would argue that the word 'transformation' needs to be reclaimed. In one of the biggest debates in the study of Classical Urbanism, discussion of the 'end' of ancient cities, the term has become baggage laden. For some, notably Ward-Perkins (2005, 4) it is too neutral to apply to what befell Rome and her empire. While for others, amongst them participants in the European Science Foundation's wide ranging 'Transformation of the Roman World Project' (https://brill.com/display/serial/TRW), it seems the best term to cover a raft of