The Roman Fort at Castell Collen was rectangular in outline, measuring about 510 feet from north-north-east to south-south-west, by about 360 feet transversely (c.155 x 110 m), within the ramparts, giving an occupation area of about 4¼ acres (c.1.7 ha). At some later date the northern defences were contracted by about 140 feet, giving an almost square outline and reducing the internal area to about 3 acres (c.1.24 ha).

At Castell Collen (Fig.6) the length of the fort (originally, it would seem a Flavian fort of ordinary type) was reduced by 40 [sic.; should be 140] feet. A cross-wall was built cutting off most of the retentura, and forming the back wall of a square castellum measuring 410 feet externally each way (i.e. probably 360 to 370 feet square internally, or 3 acres. Wheeler Prehist. and Rom. Wales, 230.)” (Collingwood, p.38)

The first excavations at Castell Collen were conducted in 1911 but the most productive were under Alcock during 1954-6. There were two main periods of occupation, the original timber-built fort on this site was of typical Flavian type and dated c.75AD. The earliest samian recovered was a piece of form 15/17 (c.55-80) and two shards of form 18 (c.60-80). Any earlier fort in the area must have been sited elsewhere, “possibly in the Crossgates – Penybont area” (Webster RAC). The lack of occupation evidence dating to the Hadrianic period may indicate that the fort was abandoned by the Roman military and the site later re-occupied. Antonine samian ware shows occupation in the late-second century, and during the Severan period the retentura of the fort was reduced in length by about 140 feet by the building of a cross-wall, thus converting the fort into a square plan with an internal width of c.365 feet and an area of about 3 acres, at the same time, the defences were replaced in stone. The only dateable material found after this is some third century pottery, which may indicate that the garrison was withdrawn sometime before the fourth (JRS 1953 p.86; Webster p.115).

RIB 3115 - Fragmentary dedication

A detachment of the Second Legion [Augusta made (this)].

⸙ [...]

The capricorn in the bottom left corner of the field identifies the legion as Second Augusta; compare RIB 2193, 2203, 2204, three of its distance slabs from the Antonine Wall. RIB 2203 and 2204, like RIB 3512 (Carpow), associate the capricorn with a pegasus, one of which may have balanced the capricorn in the bottom right corner of RIB 3115. The leaf-stop and the palm-branch would also have been repeated. Peltae, some with griffin-headed terminals, are found on eight of the legionary distance slabs from the Antonine Wall, which for the Second Legion are RIB 2203, 2204 and 2139. Griffin-headed peltae are also found on its vexillation-inscription from the Wall (RIB 2180) and on the Halton Chesters slab (RIB 1428).

The Epigraphic Evidence from Castell Collen

RIB 414 - Inscription

… father of his country, … times consul ..

[...] P P C[...]
... MA

It is probably part of a Trajanic inscription, see RIB 397-399 (Gelligaer).

There are four inscriptions on stone recorded in the R.I.B. for the Castell Collen fort. There are three ‘centurial’ stones, an ansate building-stone found within the fort in 1911 is missing the right side and reads merely > … “The century of [… built this].” (RIB 417), the other two stones were found re-used in the local area and are shown below. The remaining stone is part of an inscription recording the dedication of the principia or regimental headquarters building in the centre of the fort (RIB 414, vide supra).

RIB 415 - Centurial stone of Marcus

The century of Marcus built 46 feet.


See RIB 428 for the work of 𐆛 marc derived presumably from Tomen-y-Mur. The nomen Marcius is also a possibility. Addenda from RIB+add. (1995): Revised dimensions per Nash-Williams, quoted by (Stephens, AC 137 (1988), 103). Nash-Williams (id.) also suggests that it either came from the Antonine rebuilding in stone (cf. JRS xlvii (1957), 227 No. 5) or from the Severan stone fort. If RIB 428 belongs with RIB 420-427, and they are Trajanic (see note to RIB 420-427 below), it follows that this is a different centuria Marci.

RIB 416 - Centurial stone of Valerius Flavinus

The century of Valerius Flavinus (built this).


No commentary.

There is another fort three miles to the north-west at Dolau Gaer (SO0166) with marching camps beyond at Trefal (SO0268), St Harmon (SN9871) and Esgairperfedd (SN9269). There is also another fort lying seven miles to the south-south-east at Colwyn Castle (SO1053). In addition, to the south of the fort on Llandrindod Common there are at least eighteen military practice works (SO0559/SO0560).

Map References for Castell Collen

OS National Grid Reference: SO056628
Dimensions: c.510 x 360 ft (c.155 x 110 m)
Area: c.4¼ acres (c.1.7 ha)

References for Castell Collen

  • The Archaeology of Roman Britain by R.G. Collingwood (Methuen, London, 1930);
  • Air Reconnaissance of Southern Britain by J.K. St. Joseph in J.R.S. xliii (1953) pp.81-97;
  • The Roman Inscriptions of Britain by R.G. Collingwood and R.P. Wright (Oxford 1965); R
  • ome Against Caratacus by Graham Webster (Batsford, London, 1993);

Map References for Castell Collen

NGRef: SO0562 OSMap: LR147

Roman Roads near Castell Collen

Road: SSW (13) to Caerav (Powys) NE (4) to Dolav Gaer (Powys) Margary #621: S (17) to Castell Madoc Postulated Road: SSW (7.5) to Penmincae

Sites near Castell Collen Fort