As previously reported in Papers of the British School at Rome (Haynes et al., Reference Haynes, Liverani, Spinola and Piro2012; Reference Haynes, Liverani, Piro and Spinola2013; Reference Haynes, Liverani, Piro, Spinola and Turner2014; Reference Haynes, Liverani, Peverett, Piro, Spinola and Turner2016), the Lateran Project focuses on the archaeology of the Archbasilica of St John Lateran and its immediate surroundings. Research to date has concentrated on the extensive area, running up to 8.5 m below the modern ground surface, now exposed beneath the Basilica and Baptistery. This area contains major elements of high-status residential buildings of the early Imperial period, the southwest and central range of the Severan Castra Nova of the equites singulares, a substantial bath complex, the foundations of the Constantinian Basilica, parts of the Oratory of Santa Croce, and what has been interpreted as the Nymphaeum of Pope Hilarus. Work in the 2016 season extended the investigation to encompass a laser scanning survey of the Archbasilica's current interior. Salvatore Piro and Daniela Zamuner (ITABC, CNR), have continued to conduct integrated ground-penetrating radar surveys. Continuation of the fruitful collaboration with Lex Bosman (Amsterdam), launched last season, continues.

Work in the 2016–17 field season advanced analysis through a series of targeted studies. Completion of the laser scanning survey last season and the corresponding development of the Project database has provided a foundation for further interpretation. The integration of all subsurface scan data with the scan survey of the Archbasilica's current interior (Fig. 1) assisted greatly in the development of revised interpretations of the Constantinian Basilica's interior with Lex Bosman. Site visits were also integral to the ongoing study of other parts of the complex, notably the Castra Nova and the structural elements that Paolo Liverani provisionally has identified with the mid-fifth-century Nymphaeum of Hilarus. It need not be stressed here that, however fine laser scanning surveys of structural archaeology are, there is always a benefit from revisiting a site and reviewing it by eye.

Fig. 1. A cutaway image of the Archbasilica of St John Lateran derived from laser scans by the Lateran Project. This derives from the integrated 3D model of the Lateran used by Project members to facilitate analysis of the key spatial relationships within the complex.

Integral to the Lateran Project's plan from the start has been a desire to ensure the best possible exchange between fieldwork data and any resulting visualizations. The power of visualization to communicate complex ideas and to maximize the impact of research is of course widely recognized, and so, too, is the danger inherent in its use. The London Charter (2009), for the computer-based visualization of cultural heritage, recognizes the potential of visualization to obfuscate as much as inform, and offers valuable guidelines, not always observed. Within the Project, we have sought to maximize the potential value of computer-based modelling techniques as part of the analytical process, thinking of these concept models as much as ‘provocations’ to further dialogue as end products.

With this in mind, fieldwork and the provocations/concept models derived from it in 2016–17 both fed into and fed from a major conference held at the British School at Rome 19–21 September 2016. This conference, entitled The Lateran Basilica, took an interdisciplinary look at the Archbasilica site and its environs from the early Imperial period, three centuries or so before the Basilica's construction, to the 1600s. Feedback on the images presented at the conference by Project Members, in the case of the model of the Constantinian Basilica in partnership with Lex Bosman, has proven invaluable.

At the time of writing, team members are working with Lex Bosman to revisit points of detail within the model of the Constantinian Basilica prior to the submission of the image to a forthcoming book of the conference. Similarly, a useful challenge to our provisional interpretation of structures unearthed by Pelliccioni (Reference Pelliccioni1973) as the Nymphaeum of Hilarus, recorded in the Liber Pontificalis (48.4) has led us to re-examine the surviving opus sectile floor in this part of the scavi.

The challenges and advantages of analysing field data in the complex subterranean environment of the Lateran scavi, in conjunction with the stimulus of generating concept models with which to think, is exemplified by the work undertaken on the Castra Nova this year. An important part of the central range of the Castra Nova, together with extended sections of barrack-like buildings, was uncovered during the excavations of Josi in 1934–8 (Colini, Reference Colini1944), though other elements of the interior have also been observed during interventions in 1838, 1890, 1957, 1965 and 1977. In addition to geo-referencing these elements with the highest level of precision possible, the team has worked with Salvatore Piro and Daniela Zamuner to undertake a ground-penetrating radar survey of both the area beneath the Archbasilica and its immediate environs. Figure 2 offers a concept model of the Castra Nova as it may have appeared in the early third century ad, based on Project fieldwork and archival research. In this simplified image, the two tones reflect the levels of confidence with which the model is advanced, with the darker colour indicating a higher level of confidence.

Fig. 2. A concept model of the Castra Nova as it may have appeared in the early third century ad. Areas presented with a higher degree of confidence are represented in darker tones. The detailed rationale behind the overall image will be included in forthcoming Project publications.

Though there are clear risks in assuming that a military base for an élite unit in the City of Rome need resemble better known forts and fortresses elsewhere in the Empire, it is important to note that some of the best preserved elements of the Castra Nova can be paralleled at contemporary sites. The Principia plan is remarkably consistent with that of headquarters buildings across the Latin West, while the barracks buildings contain familiar internal subdivisions and are graced with verandas. There are, however, distinctive elements. The production of a new platform for the fort offered the builders the opportunity to construct accessible basement storage space beneath the westernmost range of buildings, a phenomenon not otherwise known from a Roman fort. More generally, despite — or perhaps because of — the effort invested in making a massive artificial platform for the fort, it is hard to escape the evidence that the site was far smaller than what we might normally expect for a cavalry regiment widely believed to have been of milliary size (that is with a paper strength of a thousand). This leads us to two suggestions: either that the actual size of the horseguard under Severus has been overestimated by scholars, or that a substantial proportion of the unit was out-posted elsewhere.

The full rationale for our model will be given in forthcoming publications by the Project, but there is still work to be done on resolving some of the issues that remain. Looking ahead, the team is now working on two publication projects. The first is the book of the British School at Rome conference on The Lateran Basilica. The second is a technical report detailing the structural archaeology of each of the elements found beneath the Basilica.