Fieldwork at Portus in the course of 2018 and early 2019 was undertaken by the Portus Project and Portus Fieldschool, and in the context of the PortusLimen Project.
Following the successful application of Electrical Resistivity Tomography (ERT) to map the trajectory and extent of the western extent of the northern Claudian mole in previous years (Keay and Hay, 2017; Keay and Kay, 2018), the technique was used in spring 20-19 to survey an area hypothesised as the location of the lighthouse of the Claudian harbour. The survey followed the same methodology, using an array varying between 26 m and 128 m depending upon the local topography. The probes were placed at regular intervals of 2 m and parallel traverses were collected at intervals of 4 m. A total of 43 profiles were collected, the location of which were guided by the published results of the 33 cores conducted between 2006 and 2007 (Morelli et al., 2011, 56). The estimated depth of the profiles ranged between 15.5 m and 4.5 m, depending on the length of the traverses. The survey did not provide clear evidence for the location of the lighthouse, as had been hoped, although this would seem to suggest that it lay a short distance to the west of the position suggested in a recent study (Morelli et al. 2011: 58 and fig. 4.6).
A geophysical survey funded by the PortusLimen project was undertaken along the line of the Claudian basin immediately to the north of the Grandi Magazzini di Settimio Severo. This work was designed to complement the Portus Project excavation of a stretch of the southern mole immediately in front of the eastern end of the Palazzo Imperiale in 2007-2009 (Keay et al. Forthcoming 2021), and the geophysical survey undertaken work on the northern mole of the Claudian basin in April 2018. Electrical Resistance Tomography survey was undertaken on the land lying between the northern façade of the Grandi Magazzini di Settimio Severo and the modern path that runs to the south of the Tenuta del Duca Sforza Cesarini, and which curves up to the north-western angle of the Palazzo Imperiale. This indicated the presence of a band of high resistance features which seemed to demarcate the southern edge of the Claudian basin, as well as some of the features that had been detected running at an angle between the Terrazza di Traiano and the northern façade of the Grandi Magazzini di Settimio Severo in the 1998-2004 geophysical survey of Portus (Keay et al. 2005: figs 5.22 and 5.23) and the Portus Project survey of this part of the port (Keay et al. Forthcoming 2021).
Southern side of the Claudian Basin
Fieldwork was undertaken in the triangle of land that lies immediately to the north of the Grandi Magazzini di Settimio Severo, and to the west of the Palazzo Imperiale at Portus. This lies at a crucial point in the topography of Portus, which lay on the southern side of the north-eastern sector of the harbour established by Claudius, and which came to form the central isthmus that separated it from the Trajanic basin from the earlier 2nd century AD. During the course of the 2nd century AD, the triangular space was defined by the Palazzo Imperiale to the east, and the Grandi Magazzini di Settimio Severo to the south. There was a close structural relationship between both of these buildings which suggests that this was a shared space that facilitated the movement of people and cargoes between the Claudian basin, the Trajanic basin and the Canale di Imbocco del Porto di Traiano. The aims of the work in this area are to better understand the significance of this key point in the topography of the central isthmus of Portus between the 4th and 6th centuries AD.
The earliest scientific description of this area was provided by Lanciani (1865). He suggested that the late Roman wall circuit (so-called Mura Costantiniane) that enclosed much of the centre of Portus ran in this area from north to south, immediately in front of the Terrazza di Traiano, the western façade of the Palazzo imperiale. Lugli (Lugli & Filibeck 1935) disputed Lanciani’s argument, but noted a series of standing structures lying immediately to the north of the Grandi Magazzini di Settimio Severo which he suggested were of late antique date. More recently, the 1998-2004 magnetometry survey of Portus (Keay et al. 2005: fig. 5.21) revealed the presence of several indeterminate structures. A better understanding of these was gained by a Ground Penetrating Radar survey undertaken by the Portus Project. (Keay et al. Forthcoming 2021). This suggested that there were a series of structures that ran diagonally across the area between the Terrazza di Traiano and the northern façade of the Grandi Magazzini di Settimio Severo, and which may be late antique or Byzantine in date. The sedimentary sequence from a deep core drilled in the area, also by the Portus Project (Keay et al. Forthcoming 2020), indicated that this was originally an area of beach deposits that silted up in the period between the establishment of the Claudian port in the mid 1st c AD and the late antique period.
A range of different techniques were used to build upon this earlier work in 2018. Firstly, a Ground Penetrating Radar survey and an Electrical Resistance Tomography produced a sequence of anomalies that seemed to confirm the line of the edge of the Claudian basin in this part of the port. Secondly, a standing building survey was undertaken to better understand the topography of the area. Cleaning of a low lying structure running along the modern path revealed the remains of an opus caementicium quay belonging to the south side of the Claudian basin. The survey also documented the remains of a substantial portico running from east to west along a section of the northern façade of the Grandi Magazzini di Settimio Severo between a point close to the western façade of the Palazzo Imperiale up to the line of the modern path which runs through the Grandi Magazzini northwards to the Claudian basin. The inner portico comprised seven barrel-vaulted tabernae set against the north wall of the Grandi Magazzini and were fronted by a standing wall pierced by a sequence of entrances. (Fig. 1) To the west, it turned a right angle, with two parallel walls running northwards on both sides of the path that runs up to the Claudian basin. In addition to this there was an outer portico that followed the east-west and south-north line of the inner portico. The portico was built from opus vittatum mixtum which suggests a date of the 4th or the 5th c AD. The function of this building is unclear, although it would have been undoubtedly involved in commercial activities taking place along the southern edge of the Claudian basin. At some stage, there was a major re-deposition of soil in the space to the north of the portico as well as some kind of embankment along the line of the Claudian basin that had been revealed by the geophysical survey.
- Keay, S., Millett, M., Paroli, L. and Strutt, K. (2005). Portus. An Archaeological Survey of the Port of Imperial Rome. Archaeological Monographs of the British School at Rome 15. London: British School at Rome.
- Keay, S. and Hay, S. (2017) Portus and Rome’s Mediterranean ports project. Papers of the British School at Rome 85: 315 – 6.
- Keay, S. and Kay, S. (2018) The Roman Ports Project. Papers of the British School at Rome 86: 317 – 20.
- Keay, S., with Graeme Earl and Fabrizio Felici (Forthcoming 2021) Uncovering the Harbour Buildings: Excavations at Portus 2007–2012 Volume I: The Surveys, Excavations and Architectural Reconstructions of the Palazzo Imperiale and Adjacent Buildings. British School at Rome Studies/Cambridge University Press.
- Lanciani, R. (1868). Ricerche topografiche sulla città di Porto. Roma: Tipografia Tiberina.
- Lugli, G. and Filibeck, G. (1935). Il Porto di Roma imperiale e l’Agro Portuense. Bergamo: Officine dell’Istituto Italiano d’ Arti Grafiche.
- Morelli, C., Marinucci, A. and Arnoldus-Huyzendveld, A. (2011) Il Porto di Claudio: nuove scoperte. In S. Keay and L.Paroli (eds) Portus and its Hinterland. London:, Archaeological Monographs of the British School at Rome 18, 47-65.