Flannán mac Toirrdelbaig was an Irish saint who lived in the 7th century and was the son of a king of Thomond. He entered Mo Lua's monastery at Killaloe and seems to have become abbot there. He is remembered as a great preacher.
Son of an Irish chieftain, Turlough he made a pilgrimage to Rome where Pope John IV consecrated him. On his return he became first bishop of Killaloe and also preached in the Hebrides. His feast day is December 18.[1]