Gerald (Garald) (d. 726/32) of Mayo, romanising reformer and abbot-bishop of Mag Éo na Saxan, was – according to his fabulous late medieval Life – born in England, son of a certain Cusperius and an unnamed queen. He received his monastic training and education with his three brothers at Lindisfarne. When the Northumbrian church separated from the Celtic tradition after the synod of Whitby in 664, Colmán (qv), last Irish abbot of Lindisfarne, departed for Ireland with a mixed party of Irish and Anglo-Saxon monks to establish a new island monastery on Inishbofin, off the coast of Co. Mayo. When a rift developed between the native Irish and Anglo-Saxon members of the group, Colmán established (c.669/70) a new monastery on the mainland for the Anglo-Saxon monks. Known as Mag Éo na Saxan, it later gave its name to the village and county of Mayo. Bede (‘Historia ecclesiastica’, iv, 4) states, ‘from its humble start it has become a great place’. Evidently, by Bede's time the monastery had converted to the Roman Easter observance. It was formerly thought that Gerald, an Anglo-Saxon, was responsible for this, but it is scarcely possible that he had accompanied Colmán on his return to Ireland, unless as a boy. Beyond that, almost nothing is known of him.
Gerald's Life is post-Norman in date, but has much unhistorical material. It relates a somewhat unsavoury incident, found independently in other Irish sources, in which St Féchín (qv) of Fore and other clerics prayed for a plague to reduce the teeming lower orders of the Irish population, but were opposed by Gerald. The plague duly came in 664/5, and decimated the population; Féchín was among the casualties, but Gerald was spared. The Martyrology of Tallaght registers his feast-day on 12 March (‘Garalt Maigi Eo cum sociis’: Gerald of Mag Éo and his companions), but it is given in the martyrologies of Gorman and of Donegal as 13 March. The Annals of Ulster note his death s.a. 732 and style him pontifex of Mayo of the Saxons, which indicates that he was a bishop.