Underlying the modern town of Caerleon are the remains of a vast and magnificent Roman legionary fortress. This was ISCA, named for the Usk or Wsyg, established in about 75 AD as the base for the Second Augustan Legion - LEGIO II AUGUSTA. The fortress lay at the centre of an extensive settlement fringed by cemeteries, covering in all an area of perhaps 100ha. It was occupied throughout the Roman period and its ruins dominated the town well into the middle ages. There have been extensive excavations and other research, including geophysical survey, which have revealed much about the plan of the fortress and its arrangement of buildings. There is a dedicated museum (NPRN 31953).

The fortress was rectangular in form with rounded corners, its walls enclosing an area of some 9.2ha. It occupies a tongue of raised ground projecting across the Wye floodplain. The remains of the fortress walls and ramparts can still be seen on the south-west side, where they overlook the massive ruins of the amphitheatre (NPRN 95650) and the site of the parade ground or Campus (NPRN 275996). Elsewhere the footings of a group of barrack buildings have been consolidated for public display (NPRN 402679) and part of the monumental bathhouse is preserved beneath a cover building.

An extensive civil settlement, or canabae (NPRN 301891), surrounded the fortress on all sides apart from the north-east, and from the fortress roads ran northwards towards Brecon (NPRN 306000) and westwards towards Cardiff (NPRN 307253). A further road (NPRN 307871) passed through the settlement at Bulmore, 2.0km to the east (NPRN 307884), before heading towards the city of VENTA at Caerwent.

Sources: Boon, G C 1972 Isca: the Roman Legionary Fortress at Caerleon, Mon. Cardiff.
see also various in Monmouth Antiquary 17 (2001)
Nash Williams Archaeologia Cambrensis 86 (1931), 99-156; 87 (1932), 48-104, 265-349
Zienkiewicz 1986 'The Legionary Fortress Baths at Caerleon' two volumes (1986)
Evans & Metcalf 1992 'Roman Gates, Caerleon' (1992)


John Wiles, RCAHMW, 29 January 2008