A diocese of Glasbury (Welsh: Clas Cynidr)[1] existed in the 10th and 11th centuries.
The Bishops of Glasbury are listed in a 14th-century manuscript.
A less reliable list of bishops was recorded by the chronicler-monk Geraldus Cambrensis (Gerald of Wales).
[2] Situated approximately 15 km (9.3 mi) northeast of Llangors,[3] it was the site of an early Christian church from at least the 950s, it may have become a suffragan diocese of St Davids.
[4] At least in its early years, the diocese appears to have enjoyed the support of the kings of Brycheiniog, and this enabled Glasbury's bishops to compete with their rivals at Ergyng, such as Euddogwy.