St Michael's Church, Llanfihangel Abercowyn, is medieval in origin, and is situated within a rectilinear churchyard some 350m south-east of Trefenty farmhouse (NPRN 17858). It is located some 400m from the River Cywin, which forms the historical boundary between the parishes of Llanfihangel Abercowin and Llandeilo Abercywin (whose Church, St Teilo's (NPRN 304153), is situated 660m south-east of St Michael's).

St Michael's was abandoned as the parish church in 1848 when the A40 turnpike road became the focus of population and New St Michael's Church (NPRN 54624) was constructed two miles to the north. The church is some 600m east-south-east of motte and bailey castle, Castell Aber Taf (NPRN 304187), the possible forerunner to the adjacent Trefenty farmhouse (NPRN 17858). There was, reputedly, a roofed passage in front of Trefenty, along which funerals, weddings and the normal congregation had a right to pass on their way to the church. No physical trace of this remains.

The church is some 370m south-west of the standing stone known as theTreventy Stone (NPRN 304157). Six gravestones, referred to locally as “Pilgrims’ Graves” are located in the churchyard, to the south side of the church. All are thought to date to the twelfth-thirteenth centuries. Two of the stones are hog-back in style. The other four are flat and depict representations of human figures, three of which resemble females. All slabs excepting one have short, circular-headed stones at head and foot: each carved with an equal armed cross within a circle on its inner side, and ornamented with cable, chevron or diamond patterns on the sides. The bones of a youth were reputedly found in one of the graves sometime before 1938, along with a number of small shells. According to local tradition, prophesy stated that should the graveyard ever be neglected, the parish would be visited by a plague of snakes.

St Michael's is said to have been infrequently attended in its formative years as a parish church. According to tradition, on one occasion the congregation consisted of the vicar and Mr Evans (and his sheep dog) of Llandilo (NPRN 17698), whose own church was in disrepair. The vicar is said to have introduced prayers with 'O Dduw, maddeu i ni ein tri; Ifans Llandeilo a finne a'r ci'. This has been translated as 'O Lord, may forgiveness for us three be found; Evans Llandeilo, myself, and the hound'. An almost identical version of the story was attributed, in 1917, to St Teilo's Church, Llandilo Abercowin.

The church, now in ruins, is a Scheduled Monument. The south and east walls still exist to roof height, and the north wall stands to a height of around 1m. Entrances are visible in the south and west walls. Traces of wall paintings were described in 1886. There is a modern concrete structure in the south-west corner of the nave.

The building originally consisted of nave, chancel, west tower with three storeys, and a spiral staircase leading to a rood loft. Internal measurements of the chancel are given as 15ft 2in width x 18ft 6in length. Measurements of the nave are given as 20ft width x 38ft 6in length, with the tower measuring 8ft square. The chancel arch and gable are thought to be eleventh century in date. The church's carved circular font dates to the twelfth century and has been removed to New St Michael's Church.

In 1907 the roofs were noted to have disappeared within the preceding few years. A circular headed doorway was described in the centre of the south nave wall. This was thought to be twelfth century, as were the remains of another similar door in the north wall, immediately opposite. Two recesses were described, adjoining the east chancel wall. The recesses were also immediately opposite one another, and thought to have served as seats. Remains of considerable corbels on either side of the altar were suggested to have served as supports for an altar beam for the display of relics.

The west nave wall was noted to be of a different date to the south, and containing a thirteenth century doorway. The chancel was extended or replaced in the fifteenth century, and the tower is thought to have been rebuilt. A rood screen and rood stair are also thought to date to this time. The remaining windows in the south nave wall are thought to be seventeenth century.

Sources include:
Dyfed Archaeological Trust 2010-2011, Medieval and Early post-Medieval Churches and Chapels: A Threat-Related Assessment
'Stray notes on the Carmarthenshire report of the Royal Commission on Welsh Antiquaries', Transactions of the Carmarthenshire Antiquarian society, 1917-1918, p5
'Trefenty: some observations and reflections', www.carmarthenshirehistorian.org
Richard Suggett, Painted Temples: Wallpaintings and Rood-screens in Welsh Churches, 1200–1800, (RCAHMW 2021)

RCAHMW 2022