Saint Cailin is the patron saint of Errismore. He was the first Bishop of Down. When he first came to Errismore he settled at a place called Daly's hill. When he was going to erect a church there, he found that the bell of Saint Flannan's church was disturbing him at his prayers, and he moved farther on towards Slyne Head where he built a small church, the remains of which are there to the present day. The place on which he built his church is now, an Island it is called Chapel Island. It was not an Island when Saint Cailin built his church. No rat could live on the Island. The right name for Errislanin is Iorrusflannain. Saint Flannain lived there. The day for visiting Saint Cailin well is the 13th November. It is kept as a holiday in Errismore.