The church was erected in the first half of the 12th century on the site of a former Roman fort from which some materials for construction were taken. At the end of the thirteenth century, the building was enlarged by the southern chapel, and then in the fourteenth century by the porch and at the end of the fifteenth century, by the western tower. In 1790 the chapel was in ruin and probably soon it was pulled down. In the mid-nineteenth century, the sacristy was erected and the windows were rebuilt. Their next modernization took place in 1880, and then the porch was transformed. Fortunately, at the beginning of the 20th century, the church was professionally renovated, which, among other things, restored late medieval windows.
The temple consists of an eight-span, rectangular nave and a chancel, which is not separated externally from the church’s corpus. Inside, during the Middle Ages, both parts were separated by a rood screen. West side of the church is dominated by a four-storey tower from the 15th century, which is very large, for a rural building. It is topped with a crenelage and has a communication tower in the south-eastern corner. A porch was added to the south wall of the nave. The church also originally had a northern transept and a chapel from the late 13th century on the southern side. The northern transept was probably removed in the 13th century to make room for a niche, containing a tombstone. Also in the 13th century, the chancel floor was raised and leveled with the nave floor. A small, single window from the 13th century is visible in the southern wall of the nave. A couple of 15th-century openings survived, among others in the eastern wall.
Website britishlistedbuildings.co.uk, Church of St Mary. A Grade I Listed Building in Llandovery, Carmarthenshire.
Website coflein.gov.uk, St Mary’s church, Llanfair ar y Bryn.