Declán of Ardmore, also called Déclán, was an early Irish saint of the Déisi Muman, who was remembered for having converted the Déisi to Christianity in the late 5th century and for having founded the monastery of Ardmore in what is now County Waterford. The principal source for his life and ministry is a Latin Life of the 12th century. Like Ailbe of Emly, Ciarán of Saigir and Abbán of Moyarney, Declán is presented as a Munster saint who preceded Saint Patrick in bringing Christianity to Ireland. He was regarded as a patron saint of the Déisi of East Munster.