Land Demarcation and the Great Roman Network

Abstract: Ancient Rome was an expansive and wealthy empire that created a trading network that relied on common language, law, money, and a system of measurement. An important component this network was the rectangular system (RS) of land demarcation known as centuriation, which was the forerunner of similar systems adopted in the US and Canada. Centuriation was a system in which land was surveyed into rectangles (usually squares) and each parcel was given and address and mapped. The system was developed in the 3rd century BCE and lasted until the fall of the Empire and was administered by a well-organized bureaucracy of land surveyors (agrimensors). This demarcation persists and can still be found in the landscape throughout the range of the former empire, especially in Italy and North Africa. The alternative to centuriation (RS) was to demarcate by defining a plot perimeter with geographical features in a system known as metes and bounds (MB). This paper examines the determinants of centuriation by developing a model in which the state chooses between MB and RS to demarcate new lands. The model emphasized the tradeoff between the higher upfront costs of RS with its more precisely demarcated borders and its network of roads and canals against MB which is less costly to establish but also does not have the precise borders and network of centuration. Our prediction is that centuriation is more likely to be chosen when the land is more valuable and when the land had no prior demarcation system in place. To test these predictions we have collected data on the locations and characteristics of over 200 centuriated landscapes in the territory of Ancient Rome. Our preliminary findings are that centuriation was adopted in flatter, more fertile lands. We also find that alignment tended to be perpendicular to rivers and streams in order to minimize demarcation costs and to facilitate a network of canals for drainage.