St Teilo's Church is situated within a roughly quadrilateral churchyard, its south-western boundary delineated by a stream, which begins as a curative well within the churchyard. Modern and historic (1st edition) Ordnance Survey mapping appears to depict a secondary enclosure, whose west and south boundary is delineated by a stream, abutting the churchyard to the south. The church site and may be early medieval in origin. The church is some370m west-southwest and 420m south-east of two possible (according to place-name evidence) bronze age standing stones and two adjacent iron age enclosures, the larger (NPRN 305303) visible as an earthwork; the smaller (NPRN 402420) visible as a cropmark. The parish had at least one former chapelry, Llanddinog Chapel (NPRN 422413). Llanhywel Church was formally annexed to the vicarage of Llandeloy by 1490, although the union is thought to be earlier. During the post-Conquest period the church belonged to the Deanery of Pebidiog. In 1307 the benefice was appropriated by Bishop David Martin to the Chapter of St Davids Cathedral, to provide chantry priests to say mass for the soul of the king. In 1313 the church, along with Llandeloy Church, was appropriation was licenced for the provision of chantry and services to the king, William de Valence and John Wogan of Picton Castle.

The church is a Grade II listed building, constructed of limestone rubble. It consists of 3-bayed nave, 3-bayed chancel, south transept (with former skew passage) and western bellcote. The church has a long and low interior with exposed stone walls, cambered tie beams to the roofs and scissor-rafters. The medieval, possibly 13th century, octagonal font has sides splayed in to a chamfered base over a circular shaft. The nave and chancel are thought to probably be 13th?14th century in date, with the transept and former skew passage dating to the 14th century. A spiral stair turret leading to the former rood loft is thought to be 16th century. A projecting passage in the north wall gives access to the pulpit and to the rood stair. The double bellcote is thought to originate from the medieval period. A vestry (or similar) was constructed south of the chancel, possibly in the early 19th century. The church was partially rebuilt in 1925?1926 to the designs of J. Coates Carter, Prestbury, Glos, to the Arts and Crafts principles of making careful use of local materials. It was restored to its medieval plan, but the chancel south wall was moved 1.5m south (the old south wall being incorporated into the inner chancel south wall). The design incorporated a fine, oak rood screen, incorporating a pulpit. The church was entirely reroofed and refloored, and most fittings also date to this time.

Sources include:
Cadw, listed buildings database
Dyfed Archaeological Trust, 2000, Historic Churches Project, Pembrokeshire gazetteer
Dyfed Archaeological Trust, 2003, Early Medieval Ecclesiastical Sites Project, Pembrokeshire gazetteer
T.J. Hughes, Wales's Best One Hundred Churches, 2006.

N Vousden, 20 December 2017