Lorcán Ua Tuathail was a 12th-century Irish prelate who served as the Archbishop of Dublin during the Norman invasion. Born in the late 1120s, he was a central figure in the reform of the Irish Church, working to align local monastic practices with Roman traditions. He previously served as the Abbot of Glendalough and was known for his diplomatic efforts during periods of intense political upheaval. Recognized for his charity toward the impoverished and his leadership during the transition of power in Ireland, he was later canonized by the Catholic Church.