St David's Church is situated within a curvilinear churchyard, bounded by the Afon Brefi on its north side. It is possible that the church was constructed on the site of a bronze age barrow. The site is thought to have been an early monastic settlement, and its oldest inscribed stone, Llanddewibrefi 1 (NPRN 275648) dates to the sixth century. The church is first mentioned in documents of the eleventh century when it was named by Rhygyfarch as the location of the Synod of Llanddewi Brefi in around 550. It was here that St David's preaching reputedly defeated St Cadoc's revival of Pelagianism. his victory aided by the miraculous uprising of the mound on which the church is built. The church has a total of six Early Christian carved stones. Llanddewibrefi 2 (NPRN 419613) is ninth century in date. Llanddewibrefi 3 (NPRN 419614) is seventh to ninth century in date. Llanddewibrefi 4 (NPRN 419615) is is later eighth to ninth century in date. Llanddewibrefi 5 (NPRN 419616) is seventh to ninth century in date. Llanddewibrefi 6 (NPRN 419619) is ninth-century or later. Together, the six stones comprise the largest concentration of Early Christian carved stones in Ceredigion. The church was a parish church during the medieval period, belonging to the Deanery of Sub-Aeron and in posession of St Davids. In 1287 Bishop Bek refounded a college of secular canons here, comprising a Precentor and twelve prebendaries, that survived until the reformation. St Brynach's Church, Llanboidy (NPRN 310033) was once a prebend of this church, as were St Teilo's Church, Trelech a'r Betws (NPRN 301864), St Deiniol's Church, Llanddeiniol (NPRN 301816) and St Michael's Church, Llanfihangel Ystrad (NPRN 420296). By 1833 the church was in private possession and its patrons were the Earl of Lisburne and R. Price Esq.

The church is a Grade II* listed building, constructed of Llanddewi Brefi rubble stone with yellow oolite and grey sandstone dressings. It consists of three-bayed nave, two-bayed chancel, three-storeyed central tower (at crossing with former north and south transepts), west porch and below-ground boilerhouse (north of porch). The medieval church was cruciform in shape The four-arched crossing dates from the thirteenth to fourteenth century and the chancel may also date to that time. The tower was added over the crossing in the fifteenth century, with the crossing vaulted at that time. It is suggested that the form of the medieval church
was in imitation of the monastic church at Llandadarn Fawr. In 1552 the tower had five bells. A rectangular font bowl dating to the fourteenth century lies loose in the chancel. The north transept collapsed between 1785 and 1805 and the south transept collapsed before 1814. The transepts were blocked at this time. The nave and south aisle were demolished and rebuilt in 1832, at which time the chancel was partially rebuilt. The nave was again largely rebuilt in 1874, to the designs of R.J. Withers, London. The octagonal oolite font dates from this time. The chancel, used as a Sunday school until 1885, was also partially rebuilt to the designs of the same architect. The church was refenestrated, refloored, reseated and replastered at this time. The church was restored in 1913, in the non-conformist tradition. The work is described as largely superficial, although the boilerhouse may have been added.

Sources include:
Cambria Archaeology, 2000, Ceredigion Churches, gazetteer, 48
Edwards, N. 2007, A Corpus of Early Medieval Inscribed Stones and Stone Sculpture in Wales: Volume II South-West Wales

N Vousden, RCAHMW, 9 December 2013