The oldest-surviving Unitarian chapel in Wales is celebrating 50 years since it was rehomed at the Museum of Welsh Life in St Fagans, Cardiff.
The chapel probably started life as a barn
Penrhiw Chapel was originally located in Dre-fach Felindre, Carmarthenshire, and was first used as a place of worship in 1777.
Although now an exhibit at the museum, it is still used for services.
Welsh Unitarians from west Wales and Cardiff are holding a special anniversary service on Sunday.
The building was originally used as a barn but was acquired by the non-conformist Unitarians to use as a meeting house.
Its capacity was later increased by the creation of a gallery in place of the upper floor.
Gerallt Nash, senior curator at St Fagans, said: "Penrhiw Chapel is a good example of an early nonconformist meeting house, where an earlier building - possibly a barn - was turned into a chapel for the Unitarians.
"Its architecture is simple, unpretentious yet effective, and is characteristic of early Welsh chapels with an earth floor and plain wooden pews.
"The size and design of the box pews on the bottom floor vary as they were built for different families, each of whom commissioned its own pew."
The building was dismantled in 1953, and was re-erected and opened to the public in St Fagans three years later.
Reverend Eric Jones, who is leading Sunday's service, said: "Penrhiw Chapel was a focal point at Dre-fach Felindre and it continues to be a central attraction to visitors to St Fagans.
"The celebration will provide an opportunity for people to recollect their memories about the chapel and celebrate the fact the building is preserved by the National Museum of Wales to be admired by thousands of people."