St Gwynllen's Church is situated within a curvilinear churchyard, some 220m north-west of Pen-y-gaer hillfort (NPRN 303877). The church was a parish church during the medieval period, belonging to the Deanery of Ultra-Aeron. At that time it was a possession of the Bishop of St Davids and lay at the centre of an episcopal grange. It was a prebend of the collegiate church at Brecon. A parsonage, Persondy, is situated some 30m to the east with a short trackway linking it to the church.

The form of the medieval church is not known. It is thought to have probably been rebuilt in the earlier nineteenth century in the same location as its predecessor. The pre-1886 church consisted of nave and chancel (without division) and had a semicircular headed west door with steps down to the nave and a similar door at the east end of the south wall. It had a west single gabled bellcote. The church was restored in 1886, to the designs of a. Ritchie, Chester.

The present church is constructed of rubble stone with grey oolite dressings (from 1886) and consists of two-bayed chancel, three-bayed nave, south porch and vestry (south of chancel west bay). At the restoration the west wall was removed and the nave was extended west by one bay. The bellcote was replaced and the porch and vestry were added. The other walls were refaced and possibly rebuilt. The west door was blocked, as wetre the windows. The church was refenestrated and two buttresses added against the north wall. The church was also reseated, reroofed and refloored, with the floor level raised by 0.3m.

In 1998 the church was noted to only be in use during the summer months.

Sources include:
Cambria Archaeology, 2000, Ceredigion Churches, gazetteer, 48

N Vousden, RCAHMW, 27 January 2014


"Stained glass window in south wall of nave of church illustrates the legend of St. Gwynlle, said to be a cousin of St. David's. Window is inscribed 'to the Glory of God and in pious memory/ of Evan Williams Vicar of Nantcwnlle/ from 1864 to 1911 this window is erected.' On brass plaque below window: 'This window was erected by the churchpeople of Nantcwnlle and friends." Taken from notes written to accompany photograph taken by Arthur O. Chater in August 1966.