In Città Alta, near the Episcopal Seminary “Giovanni XXIII” of Bergamo, during work to repave the driveway, the remains of a substantial walled structure came to light, on which stood the walls of the modern building facing onto the road.

The masonry, the stone facing of which was visible to the west, was composed of rectangular and square blocks, bonded with compact whitish mortar. It stood to a height of 2.30 m to the south and 0.80 m to the north, for a length of circa 7.30 m and was circa 1.20 m wide. It is not clear whether the wall was built up against the terrain on its east side or was originally wider and underwent subsequent alterations according to different uses and functions. On the west side the external face was visible, the stones arranged in regular courses, even though the final result was not perfect and in some parts a certain unevenness was visible, probably caused by later interventions.
A course of thin bricks (height 4-5 cm, width 12 cm) seemed to relate to subsequent alterations and adaptations. In the south part of the wall, level with the present road, a square hole (25 × 25 cm) was visible from which rainwater may have drained.

A trial trench was opened adjacent to the wall which uncovered a layer abutting the latter comprising earth and loose rubble. The layer also contained a few fragments of pottery datable to between the early medieval period and the beginning of the 20th century. The trench did not reach the wall’s foundations nor were any related floor levels found.

The construction technique used generically dates the wall to within the medieval period. The find fits into the context of via Borgo Canale, site of necropoli from the early Imperial period onwards, and largo di Porta S. Alessandro, the place where the Basilica of S. Alessandro was built, extra moenia, in the 4th century B.C. in a cemetery area near the saint’s tomb. The basilica was demolished in 1561 by order of the Venetian Republic. The complex comprised several buildings, including the chapel of S. Pietro, the bishop’s residence and that of the priests, the rectory.

Today, the tangible archaeological evidence in this sector of the city, provides no means of linking the wall to a specific building or relating it to any of the structures documented by the written sources. From the latter one learns that, at the time of the first Lombard League the tower situated in the north part of the garden of S. Alessandro and cited as the “turris nova” in 1180, may have been restored. It is also known that the walls of Borgo Canale were restored in 1345 by Luchino Visconti, and that in 1400 there existed a “porta de Vitedoga in Burgo Canali” o “porta de Vitedoga prope confinia Canonice S. Alexandri”. According to historians, this gate, demolished during the construction of the Venetian walls, was situated at the start of via Tre armi.