Openings in masonry walls in paleo Christian and medieval Roman churches. Technical, Architectural, and Construction issues

Windows are the product of a conscious choice of material and technique, related in an empirical way to the proportions of the empty and solid part of the walls. The selection of material was associated with the economic availability of materials and related to the structural possibilities of the building. The combination of different technological components allows the builders to reach the structural limits of the single building element in order to satisfy the architectural requirements of the form. In this essay, we consider the topic of openings in the late Roman and medieval Roman churches looking at the whole spectrum of building solutions and we particularly wish to clarify how these choices follow a precise structural and building process. The study of the way in which windows are organized in a wall can give us useful clues for understanding the builders’ competences and the conditioning of a culture and a society in architecture. Of course, we cannot consider the construction of wall openings without an additional overview of the general construction, but the persistence of some building features in the medieval Roman churches allows us to find a common base on which is possible to compare and to understand the different constructive strategies adopted in the Papal city over time.