St Peter's church is located in a sloping rectangular churchyard the west end fronting Llewellyn Street, the main thoroughfare.
It was built in Early English style in1888-89 to designs of F.R. Kempson and J.B. Fowler, Llandaff diocesan architects, commissioned by church benefactor Griffith Llewellyn of Baglan. It is known as the Cathedral of the Rhondda, with a fine and well-preserved interior and an important architectural landmark in the Rhondda Fawr.
The church is constructed of coursed rock-faced masonry with pink and buff Pennant sandstone dressings used to create a simple polychromy, and Welsh slate roof with ridge tiles and crucifix gable finials. It comprises of a lofty five-bay clerestoried nave with lean-to aisles, tall four-stage west bell-tower with south-west gabled porch approached by a flight of stone steps, chancel with organ loft and vestry to north and minstrels gallery and Lady Chapel to south, and a bellcote with flanking minaret-style pinnacles over the west end of the chancel.
The interior throughout is dominated by the contrasting bands of pink and buff-oloured brick and sandstone. The nave has a tie-beamed roof with arch-braces and collar purlin, the chancel a boarded wagon roof. Fittings include a wall-to-wall reredos of pink-veined marble with white marble figures under canopies; stone pulpit with red marble colonnettes; and a font comprising a pink marble cylinder on grey marble colonnettes. Stained glass includes work by W.F.Dixon.

Sources:
Cadw Listing description extracts.
J.Newman, Buildings of Wales: Glamorgan (1995), p.530.

David Leighton, RCAHMW, 28 January 2015