Capel Teilo is thought to have been a chapel of ease serving the mountain portion of the population of Kidwelly parish. The parish of Kidwelly is noted to have once had five chapels of ease, the other four being named as Llanfihangel, Coker (NPRN 31584), Cadog and St. Thomas. The chapel is thought to date to the twelfth or thirteenth century. The earliest documentary reference to Capel Teilo dates to 1593. The name appeared several more times during the seventeenth century. It had disappeared from maps by 1750, amd is said to have been ruinous by 1762. Capel Teilo is depicted on historic and modern Ordnance Survey mapping, although it is only named on first edition (1888) mapping. It is thought that this depiction, in fact, refers to a ruined farm house of the same name, noted in 1905, when it was said to be locted some 200-300 yards west of the chapel site. It is suggested that a field hedge to the north-east of the chapel may have originally been part of a bank which encircled the site. A holy well, pistyll Teilo, is noted be located to the south of the chapel site. In the nineteenth century a flight of steps were said to lead to it.

In 1905 the south wall was the only one still standing, at a height of 7-9ft, although the remains of other walls were still traceable. Measurements of the building are given as 26ft length x 15ft width. It was also noted that the interior plaster was well preserved. The chapel site was excavated in 1966-1969 by Carmarthenshire Antiquarian Society. It was noted that the building was orientated east-west and the land fell significantly towards the west through the building. Traces of an earlier building were identified, consisting of a cobbled surface underlying the current floor of irregular slabs. Remains of an earlier wall were found partly overlain by the later north wall. On the south side of the alter the earlier wall was about two feet thick and ran immediately inside the course of the later south wall. The walls were constructed of rubble stone, and measured approximately 2.5ft in depth. The possible line of an earlier apse wall was identified on the external side of the east wall.

It was noted that no structural division existed between the nave and chancel walls of the current building. The remains of a slate roof is thought to date to the thirteenth to fifteenth century, and to be contemporary with an a crude step of white stones, sited about 8ft from the east wall, and extending for 3ft from the north wall. This footing was consistent with an alter width of 7 ft.

Several burials were identified. The skeleton of a male aged about 15 years was found in a shallow grave to the east of the chapel. It was orientated east-west with the arms folded on its chest. A single copper button, of eighteenth century date, was found overlying the chest area. The skeletons of three or more infants were found in close proximity, near the south-east corner of the building. They were buried superficially and not orientated. As it was not customery for burials to take place other than in the parish church until the nineteenth century, it has been suggested that the remains represent unconsecrated burials.

Sources include:
Tierney, H.C., 1905, 'A forgotten chapel in Carmarthensire' in Transactions of the Carmarthenshire Antiquarian society, pg59-60
Bonsor, G.G., 1906, 'Interesting facts about old Kidwelly' in Transactions of the Carmarthenshire Antiquarian society, pg 152-153
Jones, G.R., 'Excavations at Capel Teilo, Kidwelly, 1966-1969' www.kidwellyhistory.co.uk/Articles/CapelTeilo/CapelTeilo.htm

N Vousden, RCAHMW, 28 September 2012