The site is of Manordeifi Old Church thought to have been occupied by a church since the 6th or 7th century, dedicated to Llawddog, a Celtic saint. From the evidence of an inscription on the bell, it is believed that it was later dedicated to Saint Lawrence. When the parish was created in the 12th century, the dedication was changed to Saint David. The nave and chancel of the present church date from the 13th or 14th century, and the porch was added at a later date. It was probably altered in the 18th century, and repaired between 1835 and 1844. It was abandoned as a parish church in 1899. The church was repaired in 1905 and again between 1948 and 1973.
The church is constructed in stone and has slate roofs. Its plan consists of a nave and a chancel, with a large west porch, a north vestry, and a single bellcote at the west end. The interior is plastered and whitewashed. The floor of the nave is paved with slates and there is a three-sided altar platform in the chancel. The church contains box pews, four of them being larger for the use of the more prominent local families; the two easternmost of these are furnished with fireplaces. Elsewhere are open-back benches. The pulpit is plain and is partly built into one of the pews. The font is square on a circular shaft and a square base. The font dates from the 13th century, while the bell is from the 15th century. In the church are a number of monuments, one of which commemorates Charles Colby who was killed by a tiger in India in 1852. Another is to the memory of the Welsh poet John Blackwell who died in 1840 and is buried in the churchyard.
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The Church of St Donatus name refers to Donatus of Zadar, who began construction on this church in the 9th century and ended it on the northeastern part of the Roman forum. It is the largest Pre-Romanesque building in Croatia.
The beginning of the building of the church was placed to the second half of the 8th century, and it is supposed to have been completed in the 9th century. The Zadar bishop and diplomat Donat (8th and 9th centuries) is credited with the building of the church. He led the representations of the Dalmatian cities to Constantinople and Charles the Great, which is why this church bears slight resemblance to Charlemagne's court chapels, especially the one in Aachen, and also to the Basilica of San Vitale in Ravenna. It belongs to the Pre-Romanesque architectural period.
The circular church, formerly domed, is 27 m high and is characterised by simplicity and technical primitivism.