Yr Hen Gapel was built on the ruins of the former Llanybri Church which was abandoned in the seventeenth-century. Originally a chapel-of-ease to Llansteffan, and dedicated to the Virgin Mary, the first documentary reference to the church dates to 1388. It was reportedly originally referred to as 'Morbricheurche'. In the sixteenth century the church was noted to posess a chalice and bells, and it is known to have still been an episcopal church in 1671. By 1790 the building had been taken over for use as a chapel by an early Independent congregation, which had been founded by Stephen Hughes around 1670. The congregation paid an annual rent to the patron at Llansteffan until they purchased the church in 1878. The chapel was closed in 1962. Following a fire in 1974, most of the structure was demolished.

The site is a Scheduled Ancient Monument and the ruin is a Grade II listed building, constructed of rubble stone. It is considered significant as the ruin of a medieval church retaining its vaulted tower, and unusual for its history as an independent chapel. The original upper portion of the tower (subsequently demolished) was reportedly battlemented. The building was altered in 1879, when the tower's upper portion was demolished and the present pyramid tower roof erected. A fire in 1974 destroyed much of the building, although the tower and part of the nave walls survived. The current remains consist of truncated west tower, east wall, and lower courses of side walls. The square tower is fourteenth century in date, with a battered base with fragmentary string course below the cambered head of the west door, which has stone voussoirs. The west elevation has a stone 'eleventh hour' clockface dated 1879, with its hands 'frozen' at five minutes to ten. There are low walls to the former nave, with a gap for the former south door. The east wall stands to some 3m. It has a battered base and a flat-headed two-light traceried east window, with trefoiled heads to the lights.

Sources include:
Cadw, 2012, Listed Buildings Database

N Vousden, RCAHMW, 23 October 2012