Cellach of Killala was a mid-6th-century Irish bishop associated with the Uí Fiachrach. According to the pseudo-historical text Betha Chellaig, he was the firstborn son of Eogan Bel, the King of Connacht. After being trained as a monk by Ciarán of Clonmacnoise, he eventually succeeded his father as ruler. His life is characterized by a complicated relationship with his mentor, who reportedly placed a curse upon him, and his eventual service as the bishop of Killala.
Life and death
Following the death of his father at the battle of Slicech, Cellach returned to the guidance of Ciarán. He later served as bishop during the reign of Tuathal Maelgarb before seeking solitude in a hermitage on Lough Conn. Tradition claims he was murdered by four students acting on behalf of Guaire Aidhne. His brother, Muiredach, reportedly sought vengeance, leading to the burial of the killers under the Dolmen of the Four Maols near Ballina.
Historical accounts
The existence of Cellach is debated because his primary biographical source, Betha Chellaig, is a later pseudo-historical work. This account contains several chronological inconsistencies. Some scholars suggest he might be the same individual as Cellan Ua Fiachrach, who is listed in the Genealogiae Regum et Sanctorum Hiberniae.