Brecon Gaer is a Roman auxiliary fort represented by a round-angled rectangular walled enclosure about 195m WNW-ESE by 146m (2.8ha). It was extensively excavated between 1924 and 1925 by Mortimer Wheeler whilst he was at the National Museum of Wales (Wheeler 1926; re-evaluated by Simpson 1963, 16-37; Jarrett 1968) with some more recent work (Casey 1970). A large area around the fort has recently been subject to geophysical survey on behalf of the Clwyd-Powis Archaeological Trust.

The fort was occupied by a unit of cavalry, some 500 strong, in the late first and earlier second century. Some form of occupation continued through to the end of the Roman period, although it is unsure what this involved.

Initially a turf and timber fort, the wall, gates and the buildings of the central range were rebuilt in stone. The internal buildings included a small bath house and a large 'riding school' or drill hall. There was an extensive extramural settlement that included several official buildings and many 'strip buildings' laid out on a network of streets. Stone funerary monuments found to the north indicate the site of a cemetery.

The remains of the west, south & east gates have been consolidated and remain on view.

Sources: Wheeler 1926 'The Roman Fort near Brecon' (Y Cymmrodor 37 1926)
Simpson in Archaeologia Cambrensis 112 (1963), 13-76
Jarrett in the Bulletin of the Board of Celtic Studies 22.4 (1968), 426-432
'The Roman Frontier in Wales' 2nd edition (1969), 48-51
Casey in Archaeologia Cambrensis 120 (1970), 91-101
RCAHMW 1986 Brecknock Inventory Volume I.2, 135-146

John Wiles, RCAHMW, 5 December 2007.