These Medieval ruins of an Augustine priory are in the Vale of Ewyas in the village of Llanthony and date from the early 12th Century.

The site is open at any reasonable time and entry is free at the time of writing.

Llanthony itself is just over the border into Monmouthshire although Capel-Y-Ffin, further up the valley is in Brecknockshire.

The name Llanthony is derived from Llandewi Nant Honddu - "the church of St David on the Honddu brook". The river that runs through the Vale of Ewyas is the River Honddu.

The Abbey Hotel was hewn out of a remaining part of the priory in the 18th century, and is still open as a pub.