Treoda Castle Mound marked the site of a medieval castle first mentioned in 1314 and probably built in the later thirteenth century. This was a manorial centre with a chapel to the south-east (NPRN 307792). In the early sixteenth century Leland noted vestiges of 'a pile or maner place'. The mound was lowered and otherwise landscaped in 1848 to form part of the garden of Plas Treoda (NPRN 20105) and the masonry discovered was used in the building of the Plas. It was finally levelled in 1966 following limited excavation.
The mound was roughly circular, 40m across at its base and 1.6-2.0m high. Before 1848 it would have been some 3.6m high. The masonry uncovered may have been a large circular tower, but this is uncertain.

Excavations showed that the mound had been raised over an earlier low turf mound some 25m in diameter. This may have been a prehistoric funerary monument and fragments of Bronze Age pottery were found. Abraded Roman tile and pottery were recovered from the surface of the turf mound and a few sherds of second and third century pottery have been recovered from the church site.
The castle mound and chapel both stood within a roughly rectangular banked enclosure some 195m north-south by 160m. It is suggested that this was a Roman fort, however the setting, within a shallow valley, makes this unlikely, as does its postion in the known Roman military dispositions in the area.

Sources: RCAHMW Glamorgan Inventory Volume I.1 Stone Age & Bronze Age (1976), 102 No. 421
Volume III.1a The Early Castles (1991), 211-5 (MM2)

John Wiles, RCAHMW, 4 December 2007