St Brynach's Church is situated within a curvilinear churchyard. The site may be early medieval in origin. An early medieval inscribed stone, was formerly located in the churchyard but is now lost. An early medieval cross-incised stone, Llanfyrnach 3 (NPRN 304111), is located some 300m west of the church, and is thought to possibly mark the location of an early cemetery site. A motte (NPRN 304112) lies some 30m to the north-west of the church. The parish had at least one former chapelry. In 1708 Llanfyrnach 1, a an early medieval inscribed stone, was noted lying beneath the alter. It had a roman-letter inscription, a transcription of which has been translated as `Of Tavusus son of?? The church was granted to Slebech Commandery around 1160. At the dissolution the church, along with all the appurtances of Slebech Commandery, fell to the Crown. It remained in royal patronage. The church was a parish church during the post-Conquest period, belonging to the Deanery of Cemais.

The form of the earlier church is thought to have been similar in size and plan to the present building. The octagonal font bowl dates to the 15th century, but its stem and base date to the 19th century. The church was rebuilt in 1842 in the same location as its predecessor, but retaining nothing from the earlier fabric. The church consists of 3-bayed nave, 2-bayed chancel and 2-storey west tower. It is constructed of slate rubble, in neo-gothic style. The nave and chancel windows are single lights with simple two-centred heads. The chancel side windows have been blocked, as were the two-light mullioned windows of the tower ? possibly in the later 19th century.

Sources include:
Dyfed Archaeological Trust, 2000, Historic Churches Project, Pembrokeshire gazetteer
Dyfed Archaeological Trust, 2003, Early Medieval Ecclesiastical Sites Project, Pembrokeshire gazetteer
Edwards, N. 2007, Corpus of Early Medieval Inscribed Stones and Stone Sculpture in Wales

N Vousden, 4 January 2018