During the excavations carried out by archaeologists in 1990, a square well, which is now no longer visible, came to light in front of the basilica of San Saturnino (fig. 1), in the square of San Cosimo. Its opening was located on the north-eastern side and was accessible via a staircase; it was closed by walls at the bottom, set on the rock and made of reused architectural materials and at the top by various stone materials bonded with mortar (figs. 2-3). The materials and stratigraphic data allow us to date it to the Roman imperial age, coinciding with the funerary use of the area.

It was restructured during the VI century by closing the entrance wall and building a circular wall all around which opened to the northeast, with an access corridor bordered by a structure on the south side. It was definitely tied in to use of the necropolis and it has been suggested that its origin could be traced to very ancient times, interpreting it as sacred well, linked to water worship. Moreover, a bovine skull was found in the foundations of the circular wall, together with a big bone, which some scholars suggest could be a deconsecrating ceremony, certainly of pagan origin but most likely already Christianised: it would seem therefore to be the transformation of a sacred well from pagan to Christian.

The area around the well was once again restored during the Middle Ages, with the partial demolition of the circular wall and the creation of square masonry pillars clad with bricks. In the modern age, the well is connected to a system of tanks by means of a conduit.

Fig. 1 - Square of San Cosimo: the well was found where the flowerbed is now (photo by Unicity S.p.A.).

Fig. 2 - Square of San Cosimo: floor plan of the well (from PANI ERMINI, SPANU 1992, p. 26, fig. 16).

Fig. 3 - Square of San Cosimo: the well during the excavations (from PANI ERMINI, SPANU 1992, p. 31, fig. 20).