Exploring Roman Caerleon: new excavations at the legionary fortress of Isca

Andrew Gardner and Peter Guest The Roman legionary fortress at Caerleon in south Wales, has been subject to archaeological investigation for more than 150 years, including the well-known amphitheatre excavations conducted by Mortimer and Tessa Wheeler in the 1920s. This retrospective link with the Institute of Archaeology has now been reinforced by a new project, organized jointly by UCL and Cardiff University, starting in 2007. Here the Directors of the project discuss their aims and the results of the first two seasons of work. site did complete a gradual transformation from a bustling Roman fortress to a medieval farming community. All phases of this process are being investigated in the current excavations.

B eneath the modern town of Caerleon, near Newport in south Wales, lie the remains of one of three long-term legionary fortresses in Britain. In contrast to the other two such fortresses, at York and Chester, that at Caerleon is relatively open to archaeological investigation, and this makes it a site of international significance. Current excavations in the fortress, conducted by a joint Cardiff-UCL team, 2 are shedding entirely new light on the interior of such a settlement, challenging the notion that Roman military archaeology has no surprises left in store. The fortress at Caerleon, Isca to its Roman inhabitants, was built in the mid-70s AD, and occupied by Roman legionaries: citizen-soldiers, who were the heavily armed infantry core of Roman armies. It, or at least the extensive community around the fortress walls, was also home to many civilians, people who lived and worked with the military. This hybrid settlement persisted for at least three hundred years, though its final stages are perhaps the least well understood, making them a particular focus for the current excavation campaign.
The beginning of Roman occupation at Caerleon is more clearly defined. After the invasion of southern Britain initiated by the emperor Claudius in AD 43, Roman armies advanced gradually to the west and the north over the next four decades. The region that became modern Wales proved difficult to conquer, but once this had happened numerous garrison-posts were established, linked by roads, and largely held by auxiliary soldiers -non-citizens recruited from the more recently conquered provinces of the empire. Although in the forefront of the conquest, the legions were deployed more as a supervisory reserve in this phase of consolidation, with two bases established during the 70s at Caerleon and Chester. These continued to be maintained even as many of the other garrisons were given up, particularly during the 2 nd century, to release troops to be deployed into the more intractable northern part of Britain. Detachments from the legions at Caerleon (II Augusta) and Chester (XX Valeria Victrix) were certainly sent north to take part, for instance, in the construction of Hadrian's Wall, but their bases remained fixed, certainly until the 4 th century. At this time, there are signs of at least partial abandonment at Caerleon (and indeed, a little later, at Chester). Legions were typically broken up into smaller detachments during this period, and it is frequently suggested that Caerleon's garrison was reduced and then moved to a new late Roman fort at Cardiff and then to Richborough, where it is listed in a 5 th century administrative document, the Notitia Dignitatum. Some soldiers may have remained, however, and continued to live at Caerleon up to and even beyond the end of Roman administration in the early 5 th century. 3 Eventually, though, the Research Committee, 5 and several new research projects, including the present one. Following a series of geophysical surveys conducted by GeoArch and Cardiff University (Fig. 1), 6 new UCL-Cardiff excavations commenced in 2007, focusing on promising areas revealed by these surveys. In Priory Field, this season included test-pitting in areas where barracks, granaries and another possible store-building had been located, and in June and July of 2008 we returned to examine the latter structure via open-area excavation.

Th e Priory Field excavations: late and post-Roman phases
Th e building upon which excavation commenced in 2008 appears to be a square structure, with a large internal courtyard surrounded by four ranges of rooms, and is some 50m long on each side. Part of the building lies under the Priory Hotel car park, but the whole of the western wing lies within Priory Field. Th is large fi eld is currently open pasture, and does not appear to have been substantially built upon since at least the Middle Ages. While the other types of structures located in the geophysical survey of Priory Field have been well documented at other sites, this particular building -interpreted as a store-building on the basis of a small number of analogies -is of a type that has not been excavated in Britain before, and not examined elsewhere with modern techniques. Furthermore, the magnetometry results gave some reason to believe that overlapping structures of a diff erent date -perhaps post-Romanmight be found, encroaching upon a yard area to the west of the main building. With these issues framing our research objectives, therefore, we opened a 20 by 25m trench in our fi rst six-week season, aiming to complete the project in a second season (now forthcoming in summer 2010). Th is trench (Fig. 2) straddled the west wing of the store-building, including parts of the internal and external yards. Th e project was also intended to provide training to undergraduates from both Cardiff and UCL (and indeed other universities), facilitate further geophysical work, and engage the public in Caerleon and beyond; more will be said on our success with the latter ambition below.
Th e preliminary results from our 2008 season can be described in terms of three main periods of activity on the site (Fig. 3): the Roman "warehouse", an intermediate phase of structures, and a Medieval agricultural building. As we have yet to reach a level where evidence of the initial timber phase of the fortress might be found, our fi rst structure is the stone "store building", probably constructed together, these pieces of evidence hint at the new phase of structures being erected in and around the partially ruined or demolished warehouse, perhaps in the late Roman period or early in the succeeding period. A small segment of rough cement flooring (opus signinum -mortar mixed with tile fragments) seemed to accompany this walling in one area. If this can be seen as a fairly direct successor to the store building phase, however, the final major structural phase appears to develop at a much greater remove. Overlying all of the remains described so far, a very brokenup flagged area in the centre of the trench appeared to be the remains of another building (Fig. 7). This was associated with a small stub of walling incorporating a re-used Roman tile as a drain, and a flag-lined pit, perhaps a grain bin. Our interpretation of this structure, cut by a probable saw pit of 14 th century or later date, is as a Medieval cow shed or stable. The sequence of buildings so far recorded thus gives a fairly complete indication of the transition from fortress into farm.
The finds recovered from the excavation are certainly suggestive of both (like other stone-phase fortress buildings) in the first half of the 2 nd century AD. This was part of the normal evolution of a Roman military base in Britain -many such sites in Wales and northern England were initially constructed fairly rapidly in timber, earth, and turf, and subsequently made more permanent with masonry architecture. The orientation of the building was as expected, running right through the trench, and although the walls had been heavily robbed, traces of the main external walls, internal partitions, and some areas of flagstone flooring were all uncovered (Fig. 4). These levels have yet to be fully exposed, and will be a focus of attention in our second season. An interesting phase of alteration to this building was also discovered, in the northeast corner of our trench, where a part of the wall facing on to the interior courtyard had apparently been dismantled, and a new flagged entranceway laid across its foundations (Fig. 5). The dating of this alteration has yet to be confirmed, but it may represent a late Roman modification to the store building.
If this feature does not elucidate the problematic later phases of Caerleon, however, another set of remains may shed important light on this period. Above the level of the masonry store building was a series of incomplete lengths of walling relating to an intermediate phase of structures. These walls were unmortared and unfounded, and yet appeared to have been built to at least one storey in height, judging from an area of collapsed walling on the west side of the trench (Fig. 6). In one place, a short wall length of this phase had been constructed directly over a partition wall from the store building phase, but at a slight offset, suggesting that its builders were not aware of the underlying masonry. In other places, though, the wall alignments seemed to respect the line of the main exterior store building wall, perhaps indicating that this had been at least partially standing. Taken the likelihood of 4 th century activity in the vicinity, and of the function of the store building. With respect to the former issue, 4 th century pottery and coinage were reasonably abundant on the site, although as yet not associated with particularly secure contexts, or definitively attributable to soldiers or other inhabitants. As well as more fairly typical domestic debris, earlier finds included some items of military equipment, such as a probable shield grip, and an inscribed lead tag which seems to refer to a consignment of textiles. These perhaps hint at the kinds of items placed in the store building. A further find perhaps gives us an unusual insight into the construction of this building: an inscription recording building work under the command of the senior centurion in the legion, the Primus Pilus Flavius Rufus. This was found adjacent to one of the intermediate phase walls, indicating reuse of earlier construction material in this phase (Fig. 8). The inscription, an unusual excavation find, featured in an exhibition at the National Roman Legion Museum following on from the 2008 excavations, and this highlights a further important element in the excavation strategy: encouraging public involvement.

Public engagement
The public profile of the excavation was raised primarily through posters and leaflets available in the Museum and across south Wales, and through our website. This site, hosted by the CBA's Community Archaeology Forum and incorporating a daily blog, received some 13000 hits during the course of the excavation season. It helped us to make contact with other media organizations, including local and national press, which further increased public interest in the site. A programme of twice-daily tours and special events through the summer attracted approximately 3000 visitors to the excavations over six weeks (Fig. 9). Many of the tours and other activities provided for the public were led or initiated by students working on the site. We also sought to engage members of the local community much more directly with the excavation, and 36 volunteers worked in the trench and on the finds. This side of the project is important not just in communicating the excitement of archaeology, but also feeds into the research agenda -through the practical help offered, or through information about previous archaeological work in Caerleon recalled by local people, for example. We aim to make this element of the project even more important in 2010, when we hope to make further important discoveries concerning both late and early Roman Caerleon. In particular,