Castell Collen is a Roman auxiliary fort occupied (though not continuously) from the 70s AD until the early fourth century in a tactically strong position overlooking the River Ithon. It is a rectangular, round-angled enclosure, originally about 182m north-west to south-east by 114m, later reduced to about 128m by 114m, defined by stone revetted and ditched banks. Trenches from extensive excavations in 1911 and 1913 are prominant on the site today and clearly visible when viewed from the air. Further excavations, focussed on the defences and an extra-mural bathhouse, were undertaken by L. Alcock between 1954 and 1957. Surface indications of further extramural structures are said to remain within a wooded area immediately south-east of the fort.

Sources: Evelyn-White 1914 (AC14), 1-58;
Alcock 1954 (Trans. Rad. Soc.24), 62-75;
1955 (Trans. Rad. Soc.25), 46-69;
1956 (Trans. Rad. Soc.26), 10-21;
1957 (Trans. Rad. Soc.27), 5-11;
1964 (AC113), 64-96;
Jarrett 1969 (Roman Frontier in Wales, 2nd ed.), 74-7;
Britnell et al. (Studia Celtica 33), 33-90.

J.Wiles, RCAHMW, 02 August 2002