Historic masonry of Middle Ages in Sardinia: materials and building techniques as motivating reasons for iconographic choices

Religious architecture of the XI-XIII centuries in Sardinia presents churches having a longitudinal shape and consisting of one, two or three naves; different types of stone and mortar are used. Both wood and stone structures are used as horizontal closing systems, even in the same building. They are adopted according to specific constructive rules originating from the tradition of Tuscany or Lombardy, which however, are reinterpreted locally, depending on available builders’ ability or the clients’ will. For instance, barrel and cross vaults may occur alternatively and occasionally arches too; on the other hand, columns, capitals and lintels spoiled from Roman buildings are often re-used. During the Middle Ages, building materials would have been available within a distance, which could be travelled in one day by an animal: masonry ashlars are a direct consequence of the geology of the building site and its nearest surroundings. In this work, the architectural heritage is studied with a multidisciplinary approach, which supplements the traditional formal/iconographical reading with a specific knowledge of both building techniques and petrographic/physical/mechanical properties of materials. This will allow redefining the Romanesque architecture of Sardinia, by reinterpreting some limits of τέχνη, which are commonly considered stylistic features, as technical driven choices.