The culture of the Roman lowlands of England extended into South Wales where two major Roman states are known, the Silures based on Caerwent and the Demetae based on Carmarthen. The boundary between them is not known, but it is usually assumed that the Vale of Glamorgan was Silurian. The Demetae state, from which Dyfed comes, was colonized and ruled by the southern Irish while Rome still governed Britain. In Vortigern's time Cunedda is claimed to have recovered Kidwelly, but the rest of Dyfed was not subdued until Arthur's time; thenceforth the dynasties of Agricola and Vortipor ruled the kingdom for centuries.
Unlike the Demetae the name Silures died with Rome. During the fifth century the dominion of Caerwent, known as Gwent, was reduced to a strip of land between the rivers Usk and Wye. After 410 the town's ruler was Honorious Ynyr, a Roman sounding name. Further, it is the only civitas capital where ordinary events of urban life were reported in the surviving texts of the sixth century. The lands west of the Usk were soon lost to Gwent and fragmented between local lords, by tradition the sons of a probably mythical Glivis. An anonymous late sixth century writer who knew this land well placed the border between Demetia and Gwent on or near the Usk and a hundred years later the Englishman Aldhelm of Malmesbury equated all South Wales with Demetia. In the early years of the seventh century Bishiop Dubricius ministered both Gwent and Glevissig [Glamorgan], but a generation later Teilo of Carmarthen is reported as both bishop of Demetia and Glevissig. Probably in 645 Glevissig threw off Demetian sovereignty and in the tenth century took the name of Gwlad Morgan, the lordship of Morgan or Glamorgan.
All of this seems to suggest that Roman life appears to have continued in Caerwent well after the time of Gildas (c.500-c.540). Medieval texts record many Roman names lingering on and the surviving inscriptions prove the point. Old fashioned Roman names like Pompeius and Turpilius, distinguished Italian names rare in the Provinces, persisted well into the seventh century. The teacher Illtud inherited a mansion on a Cotswold scale, its buildings decayed, but its estates intact. The owner of another villa near Chepstow kept the baths repaired and used them 'usually on Saturdays'. Gildas in his old age defended the abbots of these parts who travelled in carriage and pair, 'because it is the custom of the country', and speaks of well-educated monks who know more of learning and letters than elsewhere in Wales and talks of men who wined and dined in civilised comfort.
Docco or Congar, one of the earliest known of the British Saints was said to have been consecrated at either Caerwent or Exeter. He was a young man in the 430s and claimed to be the grandson of the Emperor Constantine, evidently the British Emperor of 407. His death is placed in 473 when he was said to have been an old man.
In the second quarter of the sixth century Bishop Dubricius probably had his see at Caerwent or possibly Gloucester. The town may well have been in decline at this time for between 511 and 558 a great number of well-educated men from Gwent emigrated to Brittany so that as early as the 540s it was known as Lesser Britain. Around the same time (540s) the Welsh saint Cadoc was schooled in Caerwent by an unknown Irish teacher. It may be that this was the well respected school of Tatheus which was known to have existed here.
In 584 King Mouric of Gwent defeated the Saxons under Caewlin at the battle of Tintern ford near Brockweir, where his father King Theodoric, risen from his monks cell where he had retired leaving his kingdom to his son, was killed. There was then peace for thirty years, only broken in 614 when King Idon of Gwent had to defeat a Saxon force somewhere between Monmouth and Abergavenny.
King Mouric's kingdom was partitioned on his death, but reunited by his ruthless grandson Morcant, who annexed Archenfield and Demetiae in 645 and committed a great slaughter in Gwent in 647. Morcant then attacked the West Saxons and fought two battles near Bath, one probably at Bradford on Avon soon before 655. In the period 655-8 he was reinforced by Cornovian Morfael, the last British lord of Lichfield, but in 658 they were defeated at Penselwood near Salisbury and driven back to the River Parret. Finally in 665 Morcant was defeated and probably killed in the second battle of Badon which was obviously fought between Bath and Salisbury. His son and grandsons continued his rule in the only fertile strip of Roman Britain that remained to the original inhabitants, the land where Roman letters and Roman manners lingered longest, the land where Gildas and his fellow reformers had been bred.
The above, with a few of my own observations, is taken from Morris, J., The Age of Arthur: A History of the British Isles from 350 to 650 [London, 1989], 207-8, 229-30, 254, 308, 350, 366, 410.
By the second century AD Caerwent had a population of some 2,000 souls when the inhabitants fortified the city with a ditch and rampart with four gates to the cardinal points. By the fourth century the population may have doubled. Around 290 AD the Second Augustian Legion was withdrawn from Caerleon to the Continent and around this time the rampart was fronted by a stone wall up to 23' high. The 4 stone gatehouses may have been added to the ramparts slightly earlier. Simultaneously with this refortification a second V shaped ditch was added beyond the first, possibly to take advantage of the greater height of the new walls. Around 350 AD 5 towers were added to the north curtain and 6 to the south, but none to the E&W walls. A similar refurbishment seems to have happened at Bitterne (Southampton), which functioned as a Saxon Shore Fort. As the sea came much closer to Caerwent in Roman times it is to be presumed that the town was refortified for a similar purpose. A short discussion is had on Saxon Shore forts under Pevensey.
Despite, or because of the military establishment, the buildings within the fort began to be abandoned and the town went into a steep decline. From the fourth to the ninth centuries over 150 burials took place around St Stephen's church and outside the east gate. In the eleventh century a small motte was constructed on the site of the SE corner of the wall and a bailey made internally. By 1540 the town had been reduced to 16 or 17 small cottages, built from the ruined Roman walls.
The walls of Caerwent, about a mile around, enclose an area of some 44 acres. Within this were shops, a courtyard house, a fourth century temple to Mars-Ocelus, the forum and a basilica. Of the military defences the walls remain up to 15' high in places and 3 of the 11 towers still stand, all in the SW segment. The N&S gates survive and consist of small rectangular towers projecting equally forward as backward through the walls. As the walls on either side butt against them it is to be presumed that they predate the walls. Both gates have subsequently been blocked.
The south gate is best preserved still standing some 10' high and having the bulk of the arch remaining with both capitals. Such a style in churches is regularly described as Romanesque and dated to the eleventh or twelfth centuries. The north gate is in similar condition, but is less accessible, being in a pub garden. Both the N&S gates were blocked at a date probably after 390. A portion of the south side of the east gate also remains, which shows that this followed a similar plan.
The towers added to the walls are octagonal and butt against the walls like they do against the gatehouses. Presumably these were the last phase of fortification to the site and are mid fourth century. These towers were hollow, although there were no loops. They also do not survive above the curtain height. The towers tend to about 5' in thickness, although the main curtains are generally over 7' thick. Unlike castle towers, these seem to have no internal accommodation and were presumably planked over at their summit. Other Saxon shore fort towers tend to be solid, like Cardiff and Caer Gybi in Wales and Alderney, Lympne (although at least 2 of these towers were open backed), Pevensey and Portchester where the towers may have been filled in at a later date.
Paul Martin Remfry