[1] In 668 he crossed the seas to his native land again, and on a remote island off Ireland's western coast called Inishbofin, he built a monastery and school.
This much is clearly set out in the Historia ecclesiastica gentis Anglorum of Bede, who then proceeds to describe how this led to the founding of the great school of Mayo.
Colmán sought to put an end to their dissensions, and travelling about he eventually found a place on the mainland fit to build a monastery at Maigh Eó (The Plain of the Yew Trees), translating into English as Mayo.
This was Gerald, the son of a northern English king, who, annoyed at the way Colmán's most cherished convictions had been slighted at Whitby, had resolved to follow him to Ireland.
This latter statement is not, on the face of it, improbable if Gerald, as Colgan thinks, did not live after 697; but the Four Masters give the date of his death as 13 March 726, and the "Annals of Ulster" put the event as late as 731.
Buried here was Domhnall, son of Torlough O'Conor, Lord of North Connacht, "the glory and the moderator and the good adviser of the Irish people" (d. 1176).
From the entry of 1209, recording the death of "Cele O'Duffy, Bishop of Magh Eo of the Saxons", it was long after the Synod of Kells (1152) that the monastery acquired the status of an episcopal see.
There is today little indication in Mayo Abbey village of its proud heritage, nor of its erstwhile importance in the Celtic-Anglo Saxon Christian world of the 7th and 8th centuries.