Important saint of early Ireland, founder of the monastery of Ardmore in what is now Co. Waterford; patron of the Déisi and sometimes called ‘the Patrick of the Déisi’. Details of his life are hazy; we are not certain that he lived before Patrick or in the 6th century. Declan's ancestry could be traced back to the incestuous Clothra. His traditional life contains chronological contradictions. He may have visited Rome twice, visiting Dewi Sant [St David of Wales] on the second. Many miracles are attributed to him, and he was held in great veneration. His feast-day, 24 July, was observed throughout Ireland.
See Life of St. Declan of Ardmore and Life of St. Mochuda of Lismore, ed. and trans. P. Power, Irish Texts Society, vol. 16 (London, 1916).