Flannán mac Toirrdelbaig was a 7th-century Irish saint and religious leader. Born as the son of an Irish chieftain named Toirdhealbhach, he joined the monastery of Mo Lua in Killaloe. After traveling to Rome on a pilgrimage, he was consecrated by Pope John IV, becoming the inaugural bishop of Killaloe. He was widely recognized for his preaching, which he conducted in both Ireland and the Hebrides.