Forma urbis Romae: The Severan Marble Plan and the urban form of ancient Rome.

Abstract

The Severan Marble Plan was created at the beginning of the third century A.D. under the emperor Septimius Severus. This giant wall map of Rome depicted every ground floor room in the city. Although only 10% of this artifact survives, it offers a unique view of the urban fabric of ancient Rome. The map has rarely been used to study the non-monumental parts of the city, and that is one focus of the study here. A comparison of the Severan Plan to other Roman architectural plans makes it clear that there was a developed, highly accurate tradition of Roman architectural recording. The Severan Plan was derived from this tradition, but served a symbolic purpose, simplified and abstracted from utilitarian survey plans. Comparison with archaeological remains demonstrates that the Plan is essentially accurate, though it may err in minor details. The same is shown to be true for a collection of Renaissance drawings which are the only surviving record of many lost fragments of the Plan. A typology of non-monumental architecture on the Plan clarifies many of the forms characteristic of Imperial Rome's residential and commercial structure, including apartment buildings, private houses, shops, baths, and warehouses, and shows that certain forms of apartment building, particularly a type with small living units in rows grouped around a large shared court, were very common in Rome though they are not characteristic of other Roman cities. To study the macrostructure of Rome, the Regionary Catalogues are employed. These fourth-century urban architectural census statistics offer insight into the relative structural character of the fourteen regions of Rome; they also confirm conclusions derived from the Marble Plan, that Rome's residential and commercial structure was thoroughly intermixed, as were the dwellings of the upper and lower classes. The heterogeneous composition of the urban matrix was similar throughout the city, varying more by density than by composition.