One of the few churches in Cardiff with surviving medieval fabric, the St John the Baptist was probably built in the fourteenth century but its exterior was significantly altered around 1865, probably by John Prichard. The church consists of a nave and chancel with a southern porch, northern vestry, a tall cylindrical vestry chimney projecting from the north slope of the nave roof, and a bellcote which projects sits centrally on the western end of the building. The nave and chancel are probably medieval in origin, as possibly are some of the windows. The church is built of polychromatic random rubble which is mostly a refacing or rebuilding of the original medieval walls. The eastern gables of the nave and chancel are topped with ringed crosses. The gable end of the porch and the bellcote are topped with Latin crosses with trefoil terminations. The gables of the nave, chancel, and porch are coped. The bellcote is built of stone and has pairs of trefoil-headed openings on each side. The chancel has a Perpendicular-style eastern window, which is dated internally 1915, as well as two windows with plate tracery and trefoil heads in the southern wall, one two-light and the other one-light. The nave has two trefoil-headed windows in its northern and southern walls, one one-light and the other two-light, and there is a single-light window in the western gable end. The porch is entered through a pointed archway. Internally the window arches and possibly late fourteenth-century chancel cross, as well as the medieval limestone font, highlight the medieval character of the church. The nave has a six-bay roof supported by arch-braces with moulded main beams. The chancel has a nineteenth-century four-bay wagon roof.

(Source: Cadw site report)
A.N.Coward, RCAHMW, 13.04.18