St Mary's Church was originally a chapel of ease to St John's Benedictine Priory, and since 1923 it has acted as a parish church and is the main church in the town of Brecon. There is some work from the twelfth to fifteenth centuries, and the western tower is from around 1510-1520 and was built in the Somerset style. Later repairs and restorations include those of 1831, of 1856 by T H Wyatt and of 1928 by W D Caroe. 

There are a series of wallpaintings:
1) Decalogue, creed, Paternoster (stone). 2 marble tablets with four panels; Decalogue, Paternoster, Creed. Incised & painted text, inportant initials picked out in red. Signed Stanton of Lon:, dated 1691. Probably William Stanton (1639-1705), master-mason & sculptor, sometime Master of Masons' Company; also carved monuments to Lucy family in Christ College (Gunnis 368). A rare example of metropolitan work - but cf Myddfai.[AJP '72,'94].

2) Stencilling under arch. Drawing of stencilling from under arch (1857). No trace now of drawing or paint. [AJP '72]. Refs: A.C.1857,427

Source: Richard Suggett, Painted Temples: Wallpaintings and Rood-screens in Welsh Churches, 1200–1800, (RCAHMW 2021).

RCAHMW 2021