Saint Mo Chutu mac Fínaill, also known as Carthach or Carthach the Younger (a name Latinized as Carthagus and Anglicized as Carthage), dies on May 14, 637. Mo Chutu is abbot of Rahan, County Offaly and subsequently, founder and first abbot of Lismore, County Waterford.
Through his father, Fínall Fíngein, Mo Chutu belongs to the Ciarraige Luachra, while his mother, Finmed, is of the Corco Duibne. Notes added to the Félire Óengusso, the Martyrology of Óengus, claim that his foster father is Carthach mac Fianáin, also known as Carthach the Elder, whose period of activity can be assigned to the late 6th century.
Mo Chutu first becomes abbot of Rahan, a monastery which lays in the territory of the southern Uí Néill. He composes a rule for his monks, an Irish metrical poem of 580 lines, divided into nine separate sections, a notable literary relic of the early Irish Church.
According to the Annals of Ulster, he is expelled from the monastery during the Easter season of 637. The incident is connected with the Easter controversy in which Irish churches are involved during the 7th century. Through his training in Munster, Mo Chutu is possibly a supporter of the Roman system of calculation, which likely brought him into conflict with adherents of the “Celtic” reckoning in Leinster.
Following his expulsion, Mo Chutu journeys to the Déisi, where he founds the great monastery of Lismore in modern day County Waterford. The Latin and Irish lives make very little of Mo Chutu’s earlier misfortune and focus instead on the saint’s resistance to the oppressive Uí Néill rulers and his joyous reception among the Déisi. He is portrayed in a heroic light in Indarba Mo Chutu a r-Raithin (The expulsion of Mo Chutu from Rahan).
His foundation at Lismore flourishes after his lifetime, eclipsing the reputation of the saint’s earlier church. It is able to withstand the Viking depredations which plague the area and benefit from the generosity of Munster kings, notably the Mac Carthaig of Desmond. In the 12th century, St. Déclán‘s foundation of Ardmore aspires to the status of episcopal see in the new diocese, but the privilege goes instead to Lismore.
His feast day in the Irish martyrologies is May 14, as well as in the Great Synaxaristes of the Orthodox Church. In the present calendar of the Catholic Church in Ireland, in which May 14 is the feast of Saint Matthias, the memorial of Saint Carthage is celebrated on May 15.