Today the central opening remains of the doorway-arch, mounted on two concrete pillars ( opus cementicium
) faced with large blocks of square stone and perfectly placed without mortar ( opus quadratum
). Originally, the central arch was flanked by two minor openings – lateral passages - and numerous elements of these have been recuperated during the monument's excavation. These were also used as buttresses of the central arch. The surviving arch is round with a 5 metre span. Its height from street level is 9.2 metres and its width is 4.5 metres. Three steps form the base of the pillars, approximately 6 metres wide. Rectangular recesses can still be observed on each of the two sides of the pillars but the function of these is unclear. They are identical in width and all positioned in the same manner. It has been hypothesised that they could host a special architectural element, a hypothesis nevertheless which has not been confirmed by any discoveries.
San Damiano's Arch was the monumental gateway of the city, without any defensive function, erected, like so many others, during a period of peace to serve as a solemn entrance to the town of Carsulae, which was not surrounded by a city wall.
Ciotti U., et al. (1976), San Gemini e Carsulae, Milano-Roma, Bestetti Editore