Because of the characteristic round shape of its churchyard, the Brecon cathedral is thought to be on the site of an earlier Celtic church, of which no trace remains. A new church, dedicated to St. John, was built on the orders of Bernard de Neufmarché, the Norman knight who conquered the kingdom of Brycheiniog in 1093. He gave the church to one of his followers, Roger, a monk from Battle Abbey, who founded a priory on the site as a daughter house of Battle. The first prior at Brecon was Walter, another monk from Battle. Bernard de Neufmarché also endowed the priory with lands, rights and tithes from the surrounding area, and, after his death, it passed to the Earls of Hereford, so giving it greater prosperity. The church was rebuilt and extended in the Gothic style in about 1215, during the reign of King John. In the Middle Ages, the church was known as the church of Holy Rood or Holy Cross, because it owned a great 'golden rood' which was an object of pilgrimage and veneration until it was destroyed in the Dissolution of the Monasteries in the 16th century. The smoke-blackened roof of its hall was built between 1237 and 1267.
In 1538 the Prior was pensioned off, and the priory church became the parish church. Some of the surrounding buildings were adapted for secular use; and others, such as the cloisters, were left to decay and later demolished. By the 19th century, the church was in poor repair and only the nave was in use. Some restoration took place in 1836, but major renovation of the church did not start until the 1860s. The tower was strengthened in 1914.
In recent years, some of the buildings in the cathedral close have been converted into a diocesan centre, a heritage centre and exhibition, as well as a shop and 'Pilgrims'' restaurant.
References: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.