Caister-on-Sea Roman fort and Saxon settlement


Heritage Category:
Scheduled Monument
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The building or site itself may lie within the boundary of more than one authority.

Great Yarmouth (District Authority)
National Grid Reference:
TG 51669 12296

Reasons for Designation

Saxon Shore forts were heavily defended later Roman military installations located exclusively in south east England. They were all constructed during the third century AD, probably between c.AD 225 and AD 285. They were built to provide protection against the sea-borne Saxon raiders who began to threaten the coast towards the end of the second century AD, and all Saxon Shore forts are situated on or very close to river estuaries or on the coast, between the Wash and the Isle of Wight. Saxon Shore forts are also found on the coasts of France and Belgium. The most distinctive feature of Saxon Shore forts are their defences which comprised massive stone walls, normally backed by an inner earth mound, and wholly or partially surrounded by one or two ditches. Wall walks and parapets originally crowned all walls, and the straight walls of all sites were punctuated by corner and interval towers and/or projecting bastions. Unlike other Roman military sites there is a lack of standardisation among Saxon Shore forts in respect of size and design of component features, and they vary in shape from square to polygonal or oval. Recognition of this class of monument was partially due to the survival of a fourth century AD Roman manuscript, the Notitia Dignitatum, which is a handbook of the civil and military organisation of the Roman Empire. This lists nine forts which were commanded by an officer who bore the title 'Officer of the Saxon Shore of Britain' (COMES LITORIS SAXONICI PER BRITANNIAM). Saxon Shore forts are rare nationally with a limited distribution. As one of a small group of Roman military monuments which are important in representing army strategy and government policy, Saxon Shore forts are of particular significance to our understanding of the period and all examples are considered to be of national importance.

The Roman fort at Caister-on-Sea is known from the evidence recovered in limited excavations to include many of the characteristics typical of a Saxon Shore Fort. It is also known to retain much and varied archaeological information concerning its construction, occupation and use, spanning more than two centuries of Roman occupation and also the subsequent occupation of the site during the Saxon period. Within the area of protection, many buried features and deposits up to 1.5m in depth have been shown to survive below the superficial disturbance caused by later ploughing. This fort and the associated fort at Burgh Castle are of particular interest in relation to the history of these Roman coastal defensive installations and their military function, which probably changed over time and of which much remains to be learnt. The fact that the site was reoccupied in the seventh and later centuries by what appears to have been a high status, possibly monastic community, gives the monument much additional interest. As a monument in State care and on display to the public, it is also a valuable educational resource.


The Roman fort at Caister-on-Sea is located on the north side of the Norwich Road (A1064) at the south eastern edge of the island of Flegg, c.950m east of the modern coastline and c.335m north of what was, in the Roman period, the shoreline of a large estuary which extended southwards as far as Burgh Castle and up to 12km inland. The monument includes the western part of the interior of the fort, remains of parts of the surrounding defences on the north west, west and south west sides. This area, most of which is in the care of the Secretary of State, is c.1.7ha in extent and comprises all of the fort (over one third of the total area) which is not encumbered by modern building development. Within it, evidence for subsequent occupation during the Saxon period is also known to survive.

The extent of the fort and some details of its construction and occupation during the Roman period have been established as a result of limited excavations carried out at various times between 1951 and 1972, supplemented by observations made during building works on parts of the site. It is sub-rectangular with overall maximum dimensions of c.237m north-south by c.255m, and the interior, measuring c.177m north-south by c.182m, is enclosed by the remains of defences which included a wall with an earthen bank behind it, surrounded by at least two external ditches. The ditches have become infilled but survive as buried features which have been located on all four sides of the fort. The ruined wall was described in the early 17th century as still standing above ground and, although it had been demolished by the end of the first quarter of the 18th century, the survival of buried footings and foundation trenches and of the base of the earthen bank behind them has been confirmed. Excavations carried out between 1951 and 1953 by Charles Green in the south western part of the interior also uncovered remains of buildings and other features in deposits beneath modern ploughsoil, up to a depth of more than 1.5m below the present ground surface. The footings of parts of one large stone building have been consolidated and remain exposed for public display, alongside the footings of the adjacent south wall and part of a central southern gateway. To the north east of these structures, the cobbled surface of an axial street running northwards from the gate is also visible.

The inner ditch is recorded as c.4.9m-5.5m in width and c.1.8m in depth, with a `V' shaped profile. A part of the excavated inner edge c.41.5m in length can be seen on the southern side of the monument. Beyond this, and separated from it by a berm c.3m wide, is a larger outer ditch c.10m-11m in width, dug to replace an earlier, smaller ditch, evidence for which has been recorded in several places. The wall surrounded by these earthworks was set c.2.7m back from the inner edge of the ditch, alongside which a trench to hold the timbers of a palisade was also found. The surviving foundations are constructed of mortared flint rubble and are c.2.9m wide, although the upper part of the wall was probably narrower and may have been reduced by a series of internal offsets, as observed in some other Roman forts of this type. Traces of an internal turret were found in the south eastern internal angle. The excavated western part of the southern gateway includes the base of a rectangular guard house with internal dimensions of c.1.8m east-west by c.1.6m, and foundations between 1m and 1.6m wide abutting the inner face of the wall. Post pits found between the outer face of the wall and the inner ditch, immediately to the west of the entrance, may have held supports for a timber bridge.

The interior of the fort was probably subdivided by a rectilinear grid of streets, although only two of these have been located by excavation. The metalled road running northwards from the central southern gateway along one of the main axes of the fort is c.10m wide, with two carriageways divided by a central gutter; part of an east-west street, c.5m wide and flanked by roadside ditches was also found in the north east corner.

Approximately 13m to the north of the south wall and on an almost parallel WSW-ESE alignment are the remains of a building range more than 45m in length and c.8.5m wide, divided by internal cross walls into six rooms of unequal size and with a partly excavated wing extending northwards at the western end. The outer wall footings, which are constructed of coursed flint on a core of mortared flint rubble, are between 0.69m and 0.76m wide on a wider foundation of beach cobbles, and the internal walls are c.0.5m wide, standing to a height of up to 0.5m. The superstructure of the building was probably of wattle and daub on a timber frame. Along the south side of the range is a parallel wall which is interpreted as part of a portico and would have served also to retain the inner face of the earthen bank behind the south wall of the fort. On the north side of the building are the remains of a corridor c.6m wide running along the southern and south eastern sides of a rectangular courtyard beyond. This building, below which traces of an earlier, timber structure were found, was in use during the later third and fourth centuries AD and retains evidence of various internal alterations, including a blocked opening and a hypocaust (underfloor heating system) in one room and tiled hearths inserted as secondary features in others. According to the evidence recorded in excavation, it served various domestic and industrial functions at different times and was severely damaged by fire in the later fourth century, after which it is thought to have remained at least partly ruinous.

To the north of this complex and within the courtyard area, parts of a sequence of other, possibly earlier buildings of masonry and timber were also found, together with various structures, including the remains of a corn-drying kiln and a tank c.2.4m square overall, built of flint and courses of tile with an internal rendering of plaster.

The construction of the fort is dated to the early third century AD and it was probably abandoned in the late fourth century AD. The finds include not only items of military equipment, but also numerous personal ornaments such as hair pins which are evidence for the presence of women living within the fort from at least the late third century onwards.

The fort is similar in type to the contemporary fort of Branodunum (Brancaster) on the north Norfolk coast, listed in the Notitia Dignitatum (an official list of government appointments compiled originally in the late fourth century AD) as one of the garrisons under the overall command of the Count of the Saxon Shore. It is one of the two possible sites of Gariannonum referred to in the same document, the other being the nearby fort at Burgh Castle.

The fort at Caister may also have been the `castle' near the sea, within which, according to Bede, the Irish St Fursey founded a monastery in AD 633, on land given by King Sighebert of the East Angles. The excavations within the fort, and also immediately around it, discovered many features, as well as pottery and other artefacts relating to occupation of the site from the seventh to the 11th centuries AD. Some of the objects found, such as the coins, are of a type and in quantities generally associated with high status settlements of this period. Within the fort, the ruins of the abandoned and demolished Roman buildings were found to have been extensively disturbed by later activity, including the digging of two graves, and evidence was also found for industrial activity, such as metal working, in and around an irregular hollow to the west of the site of the Roman road.

The fences and gates around the excavated area on display, together with information boards, the fences and huts of the English Heritage compound, modern path surfaces, the surface of the lay-by alongside the road to the south of the area in State care and a bus shelter on the roadside verge near the junction of the Norwich Road and Brooke Avenue are excluded from the scheduling, although the ground beneath all these features is included.

MAP EXTRACT The site of the monument is shown on the attached map extract.


The contents of this record have been generated from a legacy data system.

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Books and journals
Bede, V, The Ecclesiastical History of the English Nation132,133
Ellison, J A, 'Norfolk Archaeol' in Norfolk Archaeol, , Vol. 33, (1965), 94-107
Ellison, J A, 'Norfolk Archaeol' in Norfolk Archaeol, , Vol. 34, (1969), 45-73
Johnson, S, 'East Anglian Archaeol' in Burgh Castle: Excavations by Charles Green, 1958-61, , Vol. 20, (1983), 119-121
Margaret J Darling with David Gurney, , 'East Anglian Archaeology' in Caister on Sea: Excavations by Charles Green, 1951-55, , Vol. 60, (1993)
8675: Great Yarmouth, Caister on Sea,
Edwards, D, TG 5112/F, (1974)


This monument is scheduled under the Ancient Monuments and Archaeological Areas Act 1979 as amended as it appears to the Secretary of State to be of national importance. This entry is a copy, the original is held by the Department for Digital, Culture, Media and Sport.

End of official listing

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