St Declan founded a monastery at Ardmore Co Waterford. He was a monk-evangelist in the south in the fifth century. He was a member of the local Deisi tribe who had tribal connections with Wales; he probably learnt his monasticism in South Wales or Gaul.
Ardmore contains an oratory (cell) and holy well on the cliff side said to be the place where he lived as a hermit. It has a small stone rectangular 8 century church, called his ‘house’ i.e. his resting place, built over the saints grave. It also has a magnificent cathedral and round tower from the days of great pilgrimages. His pattern day when people gather to pray in his honour is still observed each year.