Sixteenth-century experiments of the Sangallos towards the Tuscan fortifications. The case of the Sangallo Fortress in Nettuno

The Italian coast is rich in historical architecture built for defensive purposes of the territory. In particular, the stretch of coastline starting from the fortress of Ostia and going south with Torre San Lorenzo, Torre Astura, Torre d'Anzio, and finally the Sangallo Fortress, was particularly defended in order to safeguard the agricultural hinterland, and in the case particular Neptune which was considered the "granary of Lazio". The fort was built in two years starting from 1503 by Antonio da Sangallo and can be considered one of the experiments of the architect of a new type of fortifications that merged into the construction of the Fortress of Pisa and Livorno. The Sangallo introduced the Italianstyle bastioned front with a strategic section from the defense-military point of view because it placed the besieger under direct fire from the siege's cannons. The project of the fortification develops on a square plan, about five meters high with an interlocking of sandstones and brick cladding. Around the perimeter there is a moat and at each corner there are bulwarks with retired flank with oreillon, along which there are the military posts and the slit for the cannons. The analysis of the archive documentation, the study of the sources and the geometric-digital reconstruction of the fortress would allow a deeper understanding of this innovative Sangallo scheme and focus the attention on a little studied ring of a series of sixteenth-century experiments in the military field