Carmarthen (Moridunum) Roman Fort

Flavian Auxiliary Fort (AD 69–96)

Moridunum (lit. “sea fort”) was the civitas capital of the Demetae tribe in Roman Wales and was recorded by Ptolemy and in the Antonine Itinerary. The initial fort is believed to date from about AD 75, possibly replacing the hillfort on Merlin’s Hill. The fort lasted until about 120, when the associated civilian vicus took over and the place became a town. There are two superimposed Roman forts lying in the area between St. Peter’s Church and the site of the Medieval Castle, the smaller and later fort of stone being built in the eastern corner of the earlier (and larger) timber-built fort.

Flavian Timber Auxiliary Fort

Although a Neronian base at Carmarthen cannot be ruled out, there is insufficient evidence for it. There is no reason, therefore, to doubt that the establishment of a fort at Carmarthen was part of a network established during the rapid conquest of north central and west Wales by Julius Frontinus, Governor A.D. 74–77 .

The timber fort’s dimensions are given above, the later stone fort was aligned to the north-west and measured some 130 x 100 metres (c.425 x 330 feet) – established by the discovery of a major roadway dating to this period at 33 Spilman Street in 1993 – and therefore covered an area of about 1.3 ha (c.3¼ acres).

The Stone Fort

Demolition of those buildings and the construction of a gravelled road and a clay bank over their site, interpreted as the rampart and intervallum road of a reduced fort. Associated with this reconstruction were further timber buildings and in the 1985 area a possible tanning pit and ancillary buildings.

The fort lasted until about 120, when the associated civilian vicus took over and the place became a town.

Excavations within the Fort

Excavations within the forts defences have uncovered a wealth of pottery; aside from some early Dr.29 (dated 40-75AD), the recovered samian includes examples of Flavian, Hadrianic, and Antonine wares, followed by a long gap in the pottery-record during the third century before a reappearance of fourth-century forms, and a coin of Probus and two coins of 343AD? cannot be taken as signs of occupation during the third. It would seem, then, that the fort was abandoned (or destroyed) around the Severan period and later reoccupied.

The original military defences on the site consisted of a V-profile ditch 18ft (c.5.5m) wide and 9ft (c.2.7m) deep backed by a rampart of turf and clay 19ft (c.5.8m) wide, surviving to a height of 4¾ feet (1.45m) during excavations in the north-west corner of the town in 1969. These defences were built sometime after the early-Antonine period, as attested by a samian fragment of this date which was found sealed beneath the rampart.

Civilian Walls

The original ditch (on the NW at least) was filled-in so that the settlement’s defences could be constructed, which consisted of a 58ft (17.7m) wide rampart fronted by a stone wall 5¼ ft (c.1.6m) thick. The original height of these civilian defences is not known, but must have been considerable. Several buildings were uncovered in the interior, the earliest being timber buildings dated to the early-2nd century, many of which were demolished to make way for cobbled roads and stone-built town houses by the beginning of the 3rd century.

There is a substantial Roman building nearby at Abercyfor (SN4217), and a Roman fortlet lies about fifteen miles to the west at Tavernspite (SN1813).

Literary References for Moridunum (Carmarthen) Fort

Roman name Moridunum literally translates as ‘sea fort’.

“Below the peoples we have mentioned, but more toward the west are the Demetae, whose towns are: Luentinum 15*45 55? Maridunum 15*30 54?.”

The The Geography of Ptolemy (extract above) in the early-2nd century AD assigns the Iron-Age Demetae tribe within the region of Dyfed and ascribes to them the two poleis of Luentinum and Maridunum. The first is the Roman name for the gold workings at Dolaucothi near Pumsaint, the second-named polis being the earliest mention of the Roman town at Carmarthen.

In addition to the passage from Ptolemy, the town also receives mention in the Antonine Itinerary, produced in the late-2nd century, as the south-western terminus of route number twelve of the British section. Iter XII is entitled “the route from Muridunum to Viroconium“, and details the 186 mile journey from Carmarthen, the civitas capital of the Demetae to Viroconium Cornoviorum (Wroxeter, Shropshire) the capital of the Cornovii tribe. In this itinerary the first town along the route is named as Leucarum (Loughor, West Glamorgan), which is reported as being 15 miles distant from Muridunum.

The last appearance of Carmarthen in the classical sources is thought to occur in the Ravenna Cosmology of the seventh century, where the name Macatonion (R&C#61), is listed between the entries for Glevum colonia (Gloucester) and the unidentified stations Epocessa & Ypocessa. The R.C. is notably corrupt, and it is not inconceivable that this entry has been derived from the earlier name for Carmarthen.

References for Moridvnvm [demetarvm]

  • Inventory of the Ancient Monuments in Wales and Monmouthshire – V County of Carmarthen by the RCAHMCWM (HMSO, London) pp.248/9 & fig.191;
  • Historical Map and Guide – Roman Britain by the Ordnance Survey (3rd, 4th & 5th eds., 1956, 1994 & 2001);
  • The Towns of Roman Britain by John Wacher (2nd Ed., BCA, London, 1995) pp.391-394 & fig.175;
  • Britannia xxv (1994) p.248 & fig.3 p.249; Britannia i (1970) p.125 & fig.2;
  • The Roman Inscriptions of Britain by R.G. Collingwood and R.P. Wright (Oxford 1965);
  • Air Reconnaissance in Britain, 1958-1960 by J.K. St. Joseph in J.R.S. li (1961) p.127; 

Roman Roads near Moridvnvm [demetarvm]

Possible road: SE (19) to Levcarvm (Loughor, West Glamorgan) E (13.5) to Llandeilo ENE (27) to Llandovery (Llandovery, Dyfed)

Map References for Moridvnvm

OS National Grid Reference: SN417204
Dimensions: c.600 x 400 ft (c.183 x 122 m)
Area: c.5½ acres (c.2.23 ha)
Sites near Carmarthen (Moridunum) Roman Fort