The project will utilise concepts from the modern political-scientific discourse of distributive justice in order to interrogate late antique evidence that may inform us about trends of social mobility. What is meant by social mobility for the purpose of this project is the capacity and practice of transcending legal and status categories, insofar as these are influenced by economic criteria. The project draws on a recently-completed database of data gleaned from the letters of Pope Gregory the Great, with corresponding maps (https://www.papalpatrimonies.com/map). These letters bear witness to papal interventions in controlling conditions that impacted directly and indirectly on social mobility, such as the rates of rent and taxation imposed on peasants living on church lands that were leased to farmers (conductores). The exploitation of labour is another area in which the papacy intervened in order to mitigate the excesses of demanding patrons and guarantee the relative independence of peasants. Analysis of the database already shows clearly that papal patrimonies were managed not only according to the vagaries of economic expediency but also by moral principles. Some of these principles were clearly articulated by the Pope. They sometimes have theological underpinnings but sometimes other justifications, which the project will explore.