In recent years, our understanding of Nero’s residence on the Oppian Hill has significantly improved with the acquisition of new data supplied by archaeological research organized in the East Wing by the Soprintendenza Speciale per i Beni Archeologici di Roma (SSBAR) from 2000 onwards.
The results of these excavation campaigns indicate – among other things – different choices of technique to construct the substruction galleries for Trajan’s Baths above.
These galleries have different heights and orientations: where they close off the broad open spaces of the Neronian complex – both to the east in the so-called Pentagonal Courtyard and to the west in Peristyle 20 – they follow the same north-south orientation as the earlier building and reach a greater height than those built up against the southern façade of the palace and with the same orientation as the bath complex.
We also discovered that, at least on the eastern edge, the galleries were not buried but were used as service rooms.
By contrast, for the West Wing we had no previous excavation data since, starting from the 16th century, only earthmoving work had been carried out here, aimed exclusively at freeing the rooms.
Recently, between 2009 and November-December 2011, a series of archaeological test pits were opened in the West Wing, the results of which provide fundamental data for starting conservation work.
These were limited studies, conducted in various points of the rooms forming the far western edge of the complex; the results have nonetheless allowed us to clarify the sequence of construction operations taking place in this sector.
The portico of the façade (Room 21, Trajanic Galleries, XVIII,III)
The façade of Nero’s palace was originally preceded by a portico with columns, opening southwards towards the valley with the artificial lake; today the façade is inside, concealed by the galleries later constructed to support the overlying Baths of Trajan. However, based on the findings of our soundings and the evidence from a small stretch of the portico’s foundation visible inside Gallery XVIII, we can reconstruct its whole extension, running the entire length of the palace.
Alongside the stretch of portico found during the excavation of Gallery III in 2005 a new portion was brought to light in 2009 in Room 21.
Here we also clarified the succession of the various structures: the foundation of the Neronian portico was created by chiselling away part of the wall of the adjacent Room 9, which must evidently have been built at a earlier period.
Cryptoporticus 19, Test Pit B
On the other side from the portico of the southern façade, a long corridor forms the northern edge of Nero’s palace. The data from the archaeological test pit have shown successive variations over time in this room too.
Initially, the wall on the northern edge served simply to isolate the large courtyard forming the focal point of the West Wing from the hill behind, but later – still in the Neronian period – a second wall was built parallel to the first and the vault was constructed to create the corridor, whose surfaces were adorned with the same type of fresco decorations as the other rooms in this wing.
The excavation data again indicate different phases of construction work.
In this case, however, building operations cover a time-span from the period of Nero to that of Trajan.
A sequence of buildings are constructed on the natural ground surface, here consisting of a gossan bank at an altitude of 35.37 m a.s.l. (above sea level).
The massive foundation, running north to south and forming the western edge of the complex, was built first; this was followed, perpendicular to the large wall, by the construction of the smaller dividing walls that created the various rooms. Further subdivisions of the internal spaces seem to be modifications ordered by Trajan or in any case post-dating the fire of AD 104.
The results of the recent archaeological research confirm the little information provided by scholars on this part of Nero’s palace.
In the 19th century, the architect Antonio De Romanis, as shown clearly in his drawing, described the difference between the large wall delimiting the West Wing and the later walls, and noted the sequence of buildings:
“ A wall earlier than our building… preserved to support the embankment of the hill, against which the walls of the new rooms were built”.
The test pits in the West Wing were carried out with archaeological assistance from the Cooperativa Archeologia.