Openai/693c70b0-8de8-8013-a82e-6fb23e4136ab

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User: Crymlyn bog in south wales has the ruins of an old church.

Crymlyn bog in south wales has the ruins of an old church. Know anything about that?

Assistant: Yes — that ruin on the edge of Crymlyn Bog you’ve no-doubt spotted is most likely the remains of St Margaret’s Chapel s…

Yes — that ruin on the edge of Crymlyn Bog you’ve no-doubt spotted is most likely the remains of St Margaret’s Chapel (sometimes called St Margaret’s of Coydfranke), a medieval chapel site on the western edge of Jersey Marine, just above Crymlyn Bog near Swansea. Its remains are modest — a few low walls and foundations — but the history behind them is quietly fascinating.

This site is documented as far back as 1289, when Gilbert de Clare (Earl of Gloucester) dealt with the Abbot of Neath Abbey over lands “between wet and dry land” — a poetic way of describing the edge of the bog. The chapel sat right on that fringe. Dyffryn Clydach Community Council

What we know from local historical accounts:

• St Margaret’s was a medieval religious site on elevated ground overlooking the bog and Swansea Bay. Dyffryn Clydach Community Council
• It’s likely pre-Reformation (so late Norman to medieval period) and may have been a chapel of ease or even had links with a small hermit cell or pilgrim way (St Illtyd’s Way) heading towards St Davids. Dyffryn Clydach Community Council
• Records from 1504 mention a rector’s bequest to “the fabric of the chapel of St Margaret’s of Coydffranke,” confirming active use at that time. Dyffryn Clydach Community Council
• The building likely fell out of use after the Reformation (mid-1500s) and stone from the chapel was reused locally (a common fate for monastic and ecclesiastical buildings). Dyffryn Clydach Community Council
• In renovations during the 1920s, female skeletons from the 16th century were found, hinting at burials and perhaps a broader ecclesiastical community. Dyffryn Clydach Community Council
• A holy well associated with the site (St Margaret’s Well) once sat just below the chapel, though it was lost to early 20th-century industrial work. Dyffryn Clydach Community Council

Visually today it’s subtle: low stone remnants overgrown with vegetation, easily missed unless you’re looking for them. The fact that locals and even Google searches turn up little about it means it’s one of those quiet, nearly forgotten pieces of medieval South Wales history — not a grand church ruin like Tintern Abbey, but part of the patchwork of small ecclesiastical sites that once dotted the landscape. Wikimedia Commons

If you’re curious about local archaeology or how medieval pilgrimage routes intersect with these places, this little chapel sits at a surprisingly interesting crossroads of natural bogland and deep history.