Máel Ruain of Tallaght

Saint Máel Ruain of Tallaght was the founder and abbot (and bishop) of the monastery of Tallaght in County Dublin, Ireland, and the father of a spiritual renewal in Irish monasticism in the latter half of the eighth century. He died peacefully in the year 792.

Little is known of his life. Máel Ruain was not his baptismal name but a monastic name meaning "tonsured one of Rúadán", which may show that he was a monk of Saint Rúadán's monastery at Lothra. He is believed to have obtained the land at Tallaght in 774 from Cellach, king of Leinster, and the Martyrology of Tallaght says he came there carrying relics of holy martyrs and virgins. No monastic settlement is known at Tallaght before him.

His community was the center of the movement known as the Céli Dé ("servants of God", the Culdees). His best-⁠known disciple was Óengus the Culdee, author of the versified calendar Félire Óengusso, who remembers him with gratitude as his tutor, "the great sun on Meath's south plain". His counsels and rules are preserved not in writings of his own time but in ninth-⁠century works known as the Tallaght memoir, including The Monastery of Tallaght, which draw on the sayings of the Desert Fathers and on the Conferences of Saint John Cassian. A Rule of the Céli Dé and a Latin hymn to the Archangel Michael are also ascribed to him. A later tract counts twelve of his closest followers, among them Óengus, Máel Díthruib of Terryglass, King Fedelmid mac Crimthainn of Cashel, and Diarmait of Castledermot.

The Annals of Ulster, which call him a bishop and "soldier of Christ", say that he died peacefully in 792, and the Annals of the Four Masters, probably wrongly, give 787. He was succeeded at Tallaght by Airerán. He is commemorated on 7 July as a saint of the undivided Church, by the New Calendar.