Le fortificazioni come elementi di reti difensive a scala territoriale. La Fortezza di Agrò nel territorio della costa jonica messinese

The Agrò Fortress, located on the Messina Ionian coast, is part of the fortified structures of the territory historically known as Agrò Valley, in the ancient Sicilian medieval administrative division of Valdemone, including the north-eastern portion of the island. The Agrò Valley, which the fortress controls, is a place full of residential settlements, as well as an area in the feud of pre-existing greek monasteries supported by the Normans, affected, in modern times, like others in the Messina area, by the transformations carried out by the Corps of Royal British Engineers, who came in the wake of the English army in defence of the Bourbon government in Sicily between 1806 and 1815. The historical-archival research has systematized the data of the historical maps, the indirect sources and those of the historical road network, and the relationships with the fortifications of the contemporary era, in order to reconstruct the territorial scale system of the defence of the Valley. The survey, carried out with digital photogrammetry methodology has, then, allowed to identify some stratigraphic historic sequences. The comparison between the iconographic, morpho-typological, construction data, and the partial application of the stratigraphic method of the elevations, for the central core, has allowed us to define a hypothesis of relative dating of the construction phases of the building.