St Mary's church, Llanywern was built on the site of an Early Christian church to St Cynidr. The dedication was changed to St Mary and it became a chapel of Ease to St John's Priory Brecon in the 14th century. Existing masonry is not easily datable but has been described by 'Buildings of Wales' as 14th century. There is a belfry with a pyramidal top. The windows are probably 17th century, and the porch post-medieval. The 13th century stone font is a plain bowl with a short stem and an old wood cover with a circular motif; the chancel has a late medieval lower boarded panelled ceiling with reeded ribs; the beams over the site of the rood retain traces of red paint. Wainscot panelling behind altar is dated 1657, with a floral motif to the rail and panels below. The church is lit with oil lamps.

Sources: CADW listed buildings database; T.J. Hughes, Wales's Best One Hundred Churches, 2006.

RCAHMW, 12 November 2007.