St Patrick visited Manulla which was then know as Findmagh and founded a church there and Bishop Cainnech, Patrick's monk, was put in charge.
Prior to this the area had been pagan and had a well called Slán (the healer) which the natives venerated as if it were a God. Folklore had it that a dead prophet was buried under the stone that covered the well. He had been buried there so that the water from the well might wash his bones and also because he feared fire. St Patrick instructed the locals to lift the stone but they were unable to, so Patrick and Cainnech lifted it and Patrick said to Cainnech 'Thy seed will be blessed forever'.
The church founded here became the principle church in the region and the well was later to be renamed St Patrick's Well.