Interesting results were obtained from an investigation along via S. Nicola a Nilo, during the restoration of the Istituto Filangeri, in the part of the insula occupied by the monastery of S. Gregorio Armeno in the forum area of _Neapolis_. Until the 17th century, as is visible in the Baratta plan of 1629, this was the vico di S. Luciella (previously via della Campana), a _stenopòs _ linking the median _plateia_ (via Tribunali) to the lower one (via S. Biagio dei Librai). This was later obliterated by the enlargement of the monastery of S. Gregorio Armeno. The excavations, with the aid of historical maps and archive sources, reconstructed the building sequence in the area. The _insula_ that was destroyed is being emptied and to date fourteen rooms distributed on several levels have been identified. The core samples showed that a fill of circa 3.5 m remains above the level of the ancient via della Campana. Below this level it will be possible to investigate the transformations of an _insula_ in the ancient centre, that has not been disturbed by modern interventions, from the Aragonese-Viceregal period back to the moment of the original layout, a case which is to date unique in Neapolitan archaeology.

Below the 17th century fill, rooms were uncovered belonging to a palace dating to the Viceregal period. These comprised an entrance hall and rooms distributed on two levels. The eastern frontage of the _insula_ of this period was delimited by the line of the via della Campana, coinciding with the Greek _stenopòs_ of which traces were found in the deepest levels of the excavation. One of the underground rooms of the palace reused a terrace wall or perimeter wall of Greek date that was still in use in the Roman period. This was a curtain wall of yellow tufa blocks arranged on top of three courses of orthostats, dating to the second half of the 4th century B.C. The earliest beaten road surface which came to light comprised yellow tufa chippings and off-cuts mixed with loose sand and ash. The _terminus ante quem_ for its dating was provided by the overlying beaten earth surface dating to the 3rd century B.C., in use throughout the 2nd century B.C. The western limit of the _stenopòs_ is known from the Roman imperial period onwards. Until the 2nd-3rd century A.D. the distance between the _opus reticulatum_ structures on its two sides was 2.40 m. this increased in late antiquity to 3.20 m. The road and associated network of below ground service structures reached full development at the end of the 1st century A.D. when the ground level was raised, levelling the earliest surfaces and providing a rudus for the paving of a sewer built in _opus reticulatum_. During the same period a number of buildings were constructed at the sides of the road. Use of the road continued during the following centuries with beaten surfaces datable to the 2nd-3rd century A.D. during which period an _opus vittatum_ inspection shaft was built for the earliest sewer. Use of the road was documented for the entire medieval period, until the construction of an _opus spicatum_ road linked to the Viceroy’s palace.