Fieldwork in spring and summer 2013 saw a resumption of a new phase of work on the Palazzo Imperiale that had begun in 2012. This is a 2 ha structure that is located upon an isthmus at the centre of the port, affording its occupants very clear views over the Trajanic and Claudian basins. It was established under the Emperor Trajan and was abandoned at some time during the Byzantine period. This sixth season was focused upon the range of rooms along the northern side of the complex, from the Castellum Aquae in the east (Building 1), westwards. Our fieldwork, part of a joint strategy of excavation and restoration, the latter being coordinated by the Soprintendenza Speciale per i Beni Archeologici di Roma, investigated a zone (Area K) that lies on the western side of the early twentieth-century path that bisects the complex from north to south. This is a challenging part of the site, since it involves excavation of a partially standing structure, with archaeological remains on two storeys.
This rectangular opus testaceum room, initially uncovered in 2009 (Area D), was situated on either side of the twentieth-century path that bisects the complex. The 2012 excavations (Area K) had revealed the full eastward extent of its walls, its internal layout around a central peristyle and opus spicatum flooring. The 2013 excavations focused upon the southeastern sector of the room, cleaning back surface debris to reveal the outlines of the stumps of the square pilasters that carried the vaults of the first-floor room above. Since these were on alignment with the pilaster bases identified to the west (Area D), it confirmed the working hypothesis that the room was organized around a central rectangular peristyle. The excavations also uncovered very large pieces of rubble that derived from the demolition of the overlying first floor during the Byzantine period. The survival of opus spicatum flooring on one of these suggests that the flooring on all storeys was of the same functional kind—a sharp contrast to that in Building 8 to the west.
This was a complex range of rooms on three storeys that continued the northern sector of the Palazzo Imperiale westwards. The first-floor rooms were arranged around a central peristyle (Room 8.9) that looked out northwards over the Claudian basin. Its central pool incorporated a combined light-well and rectangular cistern at ground-floor level, and on to these opened a series of vaulted rooms. Today, only the ground and parts of the first floor survive. It is noticeable, however, that while the southern side of this range of rooms continued in a straight line westwards, the outer face of the northern range of rooms overlooking the Claudian basin ran at a northwesterly angle. Excavation on the ground floor focused upon the southern stretch of Room 8.3, a north–south corridor with sloping floor that separated Building 3 to the east from Building 8 to the west. It revealed a complete stratigraphic sequence that was investigated partially, as well as a late Roman structure of unknown function built against the wall of Building 3. Most attention was focused upon the first-floor rooms 8.7 and 8.12, whose walls still stand to c. 0.75 m, with excavation uncovering the floor levels. The former was a latrine that was trapezoidal in plan and whose northern side overlooked the Claudian basin. Remains of the original Trajanic black and white mosaic floor survived, as did some associated marble veneer. In the early fifth century the whole room was completely re-designed, with the opening of a door in the western wall, the rebuilding of the latrine seating, the addition of a new mosaic floor, and the replacement of the earlier marble veneer panels with new ones. Most of this decoration was robbed out during the later fifth century AD or later. To the west of this there was a narrow north–south corridor (Room 8.11) that separated Room 8.7 from 8.12: this and an adjacent space were filled with rubble that derived from the demolition of the second floor. The latter, which was accessed from the peristyle to the south, was of a similar trapezoidal shape and also overlooked the Claudian basin. Excavation revealed that in the early fifth century AD at least, the walls and floor of this room were richly decorated, this time with opus sectile: the mortar floor still had the long body-sherds of African amphorae arranged in the form of interlocking geometric circles and lunettes that had formed the preparation layer for the overlying opus sectile floor. Room 8.9 was the peristyle that defined the west, south and east sides of the pool that was the focus of the first floor of Building 8. Excavations uncovered a polychrome mosaic floor with vegetal motifs on its eastern side, where a door provided access into Room 8. They also revealed the stylobate and column bases that defined the western side of the peristyle, including a complete corner column, made from bricks, that had collapsed across the floor of the peristyle, presumably the result of demolition during the later fifth century AD or later. Amongst the many finds from these rooms came a hoard of late Roman coins, a Byzantine decanummus of Justinian and a small bronze cross. Room 8.13, by contrast, lay to the west of corridor 8.3, with excavations uncovering evidence for the demolition of the south wall, presumably also in the late fifth century AD or subsequently. The early fifth-century AD redecoration of Rooms 8.7 and 8.12 echoes the construction of the luxurious new latrine and adjacent rooms to the south in Building 5 (Area E) excavated in 2009. This hints at an important refurbishment of this building as a whole, illustrating what must represent key official involvement at a critical period in the history of the port, and inviting parallels with similar developments at Ostia and Rome. These findings all advance our understanding of the
Building 5 (Navalia)
This 5 lies immediately to the east of the Palazzo Imperiale, and was part of the same original architectural conception. Fieldwork undertaken in 2011 and 2012 (Keay et al., 2012) revealed that it was a vast, single building measuring 240 Å~ 58 m that was organized into a series of regularly spaced units oriented from north to south. Each of these was in turn subdivided in a consistent sequence: a passage 4 m wide, three narrow bays each c. 11 m wide, a passage 4 m wide, and a wide bay c. 19 m wide. All of these building sections opened on to a quayside bordering the Claudian basin to the north and on to a quayside bordering the Trajanic hexagonal basin to the south. Previous fieldwork revealed that the building was established under Trajan, when it seems to have had some kind of ship repair or construction function, and that in the later second century AD it was converted into a battery of warehouses that continued in use until at least the later fifth century AD. The 2013 excavations aimed to shed light on the Trajanic floor of the building in one of the narrow bays (B5.2/NB4) in order to clarify the nature of the ship-related function. A small exploratory trench dug through the late second-/early third-century AD floor and suspensurae, immediately to the east of the 2012 excavation trench, uncovered traces of the later second-century AD floor, and beneath it the Trajanic floor. This was composed of loose and compacted sand that had been perforated with post-holes and which also had abrasion marks. Bronze ship nails were found, similar to those encountered in 2012. A wider trench running from east to west across the full width of the bay is planned for 2014.
Keay, S., Earl, G., Felici, F., Copeland, P., Cascino, R., Kay, S. and Triantafillou, C. (2012) Interim report on an enigmatic new Trajanic building at Portus. Journal of Roman Archaeology 25: 484–512.