Managing the marshes: An integrated study of the centuriated landscape of the Pontine plain

Abstract

The study of Roman centuriation has a long and rich tradition, and the past decades have witnessed the rise of new perspectives on these field systems. Even though these systems were considered for some time as static structures studied through metrological analyses, they are increasingly considered as dynamic elements in the management of landscapes and the reclamation of wetlands, that should be studied from a long-term perspective. Methodologically, this development has gone hand in hand with an integration of GIS-based archaeomorphological approaches, historical, geo-archaeological and, less commonly, ecological data. This paper builds on such approaches in order to study centuriation as a complex socio-economic, political and ecological phenomenon. It aims to show that the changing roles of centuriation in human engagements with the environment can only be understood by applying a framework that integrates perspectives and approaches from different disciplines. After introducing the characteristics of this integrated framework, the paper presents a case study that synthesises recent work on the centuriated landscape of the lower Pontine plain (Lazio, central Italy), an infamous marsh with a long history of (failed) reclamation projects.A GIS-based analysis of cartographic and remote-sensing imagery, including geophysical prospection data, shows that this centuriation covered an area of some 120km2 and consisted of a hierarchical system of in-field and field-bounding ditches as well as larger collectors that drained towards the sea. Palaeoenvironmental reconstructions suggest that the centuriation and several associated canals improved the hydrological structure, although such improvements may have started before.Archaeological prospections and geo-archaeological data allow us to consider both when the centuriation was established and how its role in managing and exploiting the Pontine wetland changed through time. It probably dates to the late 4th or early 3rd century BCE and presumably is one of the first of its kind. It was established in the context of Rome's territorial, economic and demographic expansion and represented a large-scale reclamation that expanded Rome's agricultural hinterland, providing dwellings, farmland and a new life for numerous colonists. But the exploitation of the Pontine wetland by a system of small farms that occupied the centuriated area proved not to be sustainable: within two centuries settlement had decreased significantly and by the Imperial period only a few sites remained, some of which represent elite-controlled estates. The decline of settlement and its associated land use system can be explained by a series of socio-economic, political and environmental factors, including Rome's on-going territorial expansion, changing elite interests in the area as well as environmental change. Individual features of the centuriation, however, remained in use for considerable time. Even though medieval and post-medieval reclamations used parcelling systems with a different orientation, the main channels associated with the centuriation remained the basis for later attempts to drain the Pontine wetland.