St Teilo's Church, now a ruin, is situated within a small, rectilinear enclosure, some 30m south-west of Pilgrim's Rest farm complex. The church lies some 80m east of the Afon Cywyn, which forms the historical boundary between the parishes of Llanfihangel Abercowin and Llandeilo Abercywin (whose Church, St Michael's (NPRN 102138), is situated 660m north-west of St Teilo's). The church lies some The original church is thought to have been constructed around 1270, by Richard Laundry. In 1917 it was reported that, when the late Mr Harries first moved to the farm at Llandilo Abercowin the parson had no congregation. On Sunday mornings he would go to his nearest neighbour and say 'Harries bach, we ought to go into the church and have a little blessing whatever'. Mr Harries was a Methodist, but usually obliged. The vicar would always say the same prayer: 'Arglwydd trugareg bendithia ni?n tri: Harries, Llandeilo, a finnau a'r ci', which has been translated as 'O Lord, may forgiveness for us three be found; Harries, Llandeilo, myself, and the hound'. This story has also been attributed to nearby St Michael's Church, Llanfihganel Abercowin.

The building consists of nave and chancel, and measurements are given as 60ft x 27ft. The east end is thought to have been extended around 1500, at which time a south porch may have been added and the west door blocked. In 1917 two masses of rough masonry, thought to be butresses, were noted either side of the communion table. A heavy earthern mound was noted against the east wall. A small double lancet window in the west gable (above the blocked wesrt door) was thought to possibly be original. All other windows were noted to have wooden frames. The floor was described as flagged, apart from a few yards of concrete at its east end. The alter rails and round font were described as 'plain', and there was a small stoup near the south door. The pulpit was described as 'a three-decker of rude construction, but of highly interesting arrangement'. Benches were described as 'extremely primitive'. In 1973 the church was roofless. In 1962 it was noted that a Sunday service had been held inside the church in 1950, and that the building had only recently become completely derelict. At that time it had been converted to a pigsty, and the seating and communion rails had been ripped out. The pulpit was noted to have been vandalised. The site is now a Scheduled Ancient Monument.

Sources include:
'Trefenty: some observations and reflections', www.carmarthenshirehistorian.org
'Stray notes on the Carmarthenshire report of the Royal Commission on Welsh Antiquaries', Transactions of the Carmarthenshire Antiquarian society, 1917-1918, p5

N Vousden, RCAHMW, 11 June 2013