In 2005 the rescue excavation inside Palazzo Donnaregina was concluded. The excavation undertaken prior to the creation of the Naples Museum of Contemporary Art (“Madre”), brought to light various structures. In the central part of the south courtyard a cuniculus on a north-south alignment was identified as probably belonging to a water supply system, perhaps a secondary branch of the Serino aqueduct. The cuniculus, excavated as a tunnel, was later closed by a barrier in its southern part.

In the north-eastern corner of the same courtyard a cistern with two small niches with depressed arches came to light. Access to the cistern was to the east via a ladder placed up against the south wall. The first installation of the cistern was dated to the 1st century B.C. by the presence of an opus reticulatum facing on the dividing wall between the ladder and the cistern space. There was no link between this cistern and the cuniculus described above, however, it must be imagined that this reservoir belonged to a domus, which may have been occupied until the 6th-7th century A.D. The large pits containing dumps of building materials date to this period: fragments of frescoed walls, opus signinum floors and architectural elements which probably came from the destruction of the building which occupied the insula.

In a later period the cistern was substantially modified: the entrance to the east of the space was closed by a wall of small quadrangular blocks, whilst pipes connected to a manhole fed into the reservoir.
These transformations may have related to a new form of occupancy documented by a number of Byzantine structures. From this moment onwards the sector of the southern courtyard to the east of these structures was occupied by a large cemetery area which seemed to have been in use until the 12th century. Sixty-four superimposed burials on several levels were identified, all were in earth graves and there were no grave goods.