Castledykes
Roman Fort (Roman)
Site Name Castledykes
Classification Roman Fort (Roman)
Canmore ID 47721
Site Number NS94SW 7.01
NGR NS 92864 44258
Datum OSGB36 - NGR
Permalink http://canmore.org.uk/site/47721
- Council South Lanarkshire
- Parish Carstairs
- Former Region Strathclyde
- Former District Clydesdale
- Former County Lanarkshire
NS94SW 7.01 92864 44258
(Formerly NS94SW 7)
(NS 9290 4425) Castledykes (NAT) Roman Fort (R)
OS 6" map (1958)
Roman Fort, Castledykes: The Romans established sizable garrisons here in both the Flavian and Antonine periods. The superimposed remains of their successive forts lie on the edge of the escarpment 60m SE of Corbiehall farmhouse. Although almost the entire perimeter of the defences can be traced above ground, the only substantial remains are on the E, where the rampart survives to a maximum height of 1.5m above the level of the interior. Most of our knowledge of the history of the fort derives from excavations carried out between 1937 and 1955 (A S Robertson 1964), but air photographs have revealed the presence on the same plateau of at least three temporary camps and four enclosures (see NS94SW 7.00 and NS94SW 7.02 - 7.06 and 16) all now totally levelled by cultivation.
Flavian Fort: Although two subsequent occupations had destroyed or obscured much of the defences, excavation showed that the Flavian fort, which faced S, measured internally about 174m by 160m. The rampart, built of turf and earth, was at least 6m thick, and in front of it were from two to five ditches. The relatively shallow innermost ditch was 2.3m in average width, but the original dimensions of the rest are uncertain, since they were recut in the Antonine period. (Internal details and discussion of the garrison are given.) An unusual feature (X on plan) was a discontinuous ditch, measuring on average only 1.9m wide and 0.75m deep, which was traced round the E half of the fort outside the defences already described. A short section of what was presumably the same ditch was also found on the N side of the W gate, although between that gate and the one on the N it had otherwise been destroyed by the outer ditch of the fort, while more recently it has been revealed as a crop-mark to the S of the W gate. No fewer than seven entrances were located in this outlying ditch, and at three of them the ditch terminals were either staggered or made to overlap in a manner unusual in Roman castramentation. The excavator suggested that the ditch represented an Agricolan defensive enclosure which was replaced later in the Flavian period by a permanent fort, but it has also been interpreted as a contemporary outwork; a more likely explanation may be that it was a purely temporary defence thrown up by troops building the fort itself. The character of the relatively abundant 1st century material recovered from the site (now in the Hunterian Museum, Glasgow) suggests that the Flavian fort was built at the end of Agricola's third or fourth campaign, and abandoned shortly after his recall in AD 84 or 85.
Antonine Fort: The fort built on the same site about AD 142 differed little from its predecessor in plan and internal dimensions, but the addition of an outer revetment of turf increased the thickness of the rampart to 9.1m. All the ditches that had protected it in the Flavian period were now recut, with the exception of the hook-ended ditch on the W front and the narrow innermost ditch, both of which were packed and levelled, the latter to provide a firm base for the stone-cradled face of the new rampart. The Antonine ditches varied considerably in size, measuring from 2.7m to 12.0m in width and from about 0.8m to 2.7m in depth. At the same time an outer annexe measuring internally 76m by 26m was provided on the E half of the N front, possibly to serve as a waggon park.
The position of the gates was approximately the same as in the Flavian fort, but it was possible to recover the plans of only those on the N and S (details of these, the interior, and garrison are given).
After a brief period of abandonment at some time in the decade AD 150-160, the fort was reoccupied wth only minor alterations to the defences and a certain amount of internal reconstruction or repair. The enclosure attached to the E half of the N front was either reduced in area or put out of commission by the digging of a third ditch immadiately outside the existing pair; the consquent need for more storage space may have been met by the construction, further out on the same side, of a new enclosure (H on plan) whose NE corner appears as a crop- mark on air photographs. Alternatively, it may have been now that the subrectangular ditched enclosure (F) that straddles the road 60 m E of the fort was physically linked to it as an annexe (see NX94SW 7.07). The enclosure was constructed at some time in the Antonine period, and its wide entrances suggest that it originally served only a temporary purpose, possibly to accommodate the labour force engaged in building the Antonine fort. Subsequently, however, it seems to have been used as an extramural settlement or working-area, for its W ditch was deliberately filled and the N side continued westwards, as if to link up with the main defences; extensive disturbance of the ground made it impossible to confirm that there had been a corresponding westward extension of the S side. The data and purpose of the line of ditch 'G' shown by crop-marks to intersect the S side of the enclosure, were not determined by the excavation. (The name 'Castledykes' applied to the site apparently occurs for the first time in 1757).
RCAHMS 1978, visited 1975
Surveyed at 1:2500.
Visited by OS (EGC) 6 February 1968
Inspection of aerial photographs taken in 1984 suggests a possible eastward extension of the eastern annexe, which would roughly double its area. Another annexe may be defined by ditches linking the right bank of the Clyde to the southern defences of the fort (see 7.07-7.08). (Information from Gordon Maxwell)
S S Frere 1988
Aerial Photographic Transcription (29 July 1994)
An aerial transcription was produced from oblique aerial photographs. Information from Historic Environment Scotland (BM) 31 March 2017.
