Fieldwork in 2011
A fourth season of excavation was undertaken at Portus between late March and early May 2011. While this falls within the AHRC funded Portus in the Roman Mediterranean project, it represents a continuation of earlier excavations in 2007, 2008 and 2009 undertaken by the AHRC-funded Portus Project. The work was directed by Simon Keay (University of Southampton/British School at Rome (BSR), with Graeme Earl (University of Southampton), Fabrizio Felici (Parsifal Cooperativa, Rome), Stephen Kay (BSR), Roberta Cascino (BSR), Penny Copeland (University of Southampton) and Christina Triantafillou, with the assistance of a team of archaeologists from the University of Southampton and BSR, the Università di Roma La Sapienza and professional Italian archaeologists.
The area chosen for excavation was Building 5, which lies immediately to the south-east of the Palazzo Imperiale at the centre of the port. This was part of a larger complex of buildings that were centred upon the Palazzo Imperiale ab initio in the late Trajanic period. Work in 2008 and 2009 had exposed a stretch of the northern façade of the building that had been incorporated into the later 5th century AD fortifications (Mura Costantiniane), as well as uncovering the northern end of what appeared to have been a passage and staircase. The results of the 2011 excavations, together with a re-analysis of standing structures, surface undulations and geophysical anomalies (GPR and magnetometry) suggest that Building 5 was a single massive structure that comprised three discrete sections (Building sections 5.1, 5.2 and 5.3) and ran for c. 247m eastwards from the western façade of the Palazzo Imperiale to the angle at sides VI and I of hexagonal Trajanic basin. Current indications are that this building was a shipshed (navalia) comprising of multiple vaulted bays that stood up to c. 18m high and opened on to the basin (Keay, Earl, Felici et al. 2012). Each of the building sections was comprised of the following sequence of built spaces: (1) a passage c. 4m wide, (2) three parallel narrow bays c.11-12m wide, (3) a passage c.4m wide, (4) a wide bay c. 20m wide. The March to May 2011 excavations (sondage 1) focused primarily upon the north and eastern side of the westernmost section of the Building section 5.1, and specifically upon the area immediately to the south of a staircase initially revealed in 2008 and 2009. They uncovered remains of the piers that defined the western side of one of the wide bays of the building and an associated floor level whose construction can be dated to the Trajanic period. Careful excavation adjacent to the modern path to the west of this, revealed the adjacent passage (c. 4m wide).
During a fifth season of excavation undertaken in July, and again between late August and November, with the same team as in the fourth season, in conjunction with Angelo Pellegrino and with support from the Soprintendenza Speciale per i Beni Archeologici di Roma (SSBAR). Attention was focused upon Building section 5.2, and specifically upon the passage (sondage 2) and one of the narrow bays (sondages 3 and 4) immediately to the east of it. The latter confirmed earlier indications that the narrow bay was c. 11.50m wide, and that it was defined on its western side by eight piers integrated within a north-south wall, and by eight free-standing piers on the east. Enough survived of the Trajanic floor to reveal two lines of stake-holes running from north to south, as well as marks of abrasion and a deposit of bronze ship tacks on its surface. Less survived of the flooring in the adjacent passage.
The excavations also revealed good evidence for significant structural changes to Building 5 in the later 2nd,, and again at the beginning of the 3rd centuries AD. They are best understood in the context of other structural developments in the Palazzo Imperiale itself, the establishment of the Grandi Magazzini di Settimio Severo, and in the eventual unification of all three into a single complex. As with the Palazzo Imperiale itself, there were major changes in the functions of Building 5 in the 5th and 6th centuries AD. Following the demolition of much of the complex, the fortifications (Mura Costantiniana) were constructed along its northern side in the later 5th century AD, although there was provision for a small gateway that was eventually blocked in the earlier 6th century AD. The same time period also saw the spread of burials within the ruins of Building 5, as was also the case within the Palazzo Imperiale.