Fomerly the Priory Church of St John the Evangelist, dating back to the twelfth century, when the church was founded as a cell of Battle Abbey (Sussex). Much of the church was built during the thirteenth and fourteenth centuries, with numerous subsequent alterations. The church was home to the famous Brecon rood and the large decorated twelfth century font remains in the nave. Following the dissolution in 1536, the building served as the parish church until the creation of the new diocese for Swansea and Brecon, when the priory church was made its cathedral. Modern restorations by George Gilbert Scott (1861–72) and W.D. Caröe (1925–37).