 Faithleach was one of the four sons of Fionnlugh mac Olchú, and a brother of Brendan of Clonfert.His other brothers were Domhainghin of Tuaim Múscraighe and Faolán of Ceall Tulach.His associated with Cloontuskert, located in south-east County Galway, is unclear but he may have been its founder or an immediate successor.