The buildings are part of a list of structures associated with "Longobards in Italy, Places of Power (568–774 A.D.)", that is dating to the Lombard era of the early middle ages.
During the long period of the pax longobarda the group of buildings at Torba lost its military function and acquired a religious one, thanks to the settlement here in the 8th century of a group of Benedictine nuns, They led to the construction of a monastery, adding to the original structures further buildings to accommodate the cells, the refectory and the oratory, as well as a portico of three arches to shelter travelers and pilgrims.
Torba lost all monastic connection, and the buildings were converted to purely utilitarian agricultural purposes: the portico was walled up, the entrance to the church was widened so that it could be better used as a store for carts and tools, and the frescoes were whitewashed over.
[3] The church, dedicated to the Virgin Mary, was built in several phases between the 8th and 13th centuries, using stones collected from the river Olona bound with sand and lime.
The interior contains traces of an earlier ecclesiastical structure: the remains of a campanile with a square outline, pre-dating the present construction, are still visible.
The upper perimeter is decorated with "hanging" or inverted arches in cotto brick, which create an interesting chromatic effect popular in Lombard Romanesque architecture.
Inside the church, some tombs have been rediscovered and a crypt with an ambulatory, datable to the 8th century, which is reached by two flights of stone stairs set into the side walls.
The portico was a provision for pilgrims and travellers, who were thus enabled to rest under its cover and to make use of the oven near which is the stairway leading to the upper floor of the tower.
The scraps of fresco remaining on the walls and the niches cut into them are evidence that in the Lombard period this room was used as the burial place of the abbesses.
Among those frescoes still legible can be made out the figure of a nun which has in the inscription the typically Lombard name of Aliberga, and a cross with the Alpha and Omega on the horizontal arms.