The Latin Life was written c. 1400 by Augustine mac Graidín, who belonged to the Saints' Island on the southeastern shore of Lough Ree, south of the present-day village of Newtowncashel.

The same note also names him Moéca, which is explained as meaning "backslider": when Féchín felt aggrieved over the reward he received for herding the oxen of Ciarán of Clonmacnoise, he left in anger, going eastwards.

[6] The first monastic houses said to have been founded by Féchín are those on the islands of Omey and Ardoilén, both off the coast of Galway, which fell under the protection of the king of Connacht, Guaire Aidne mac Colmáin.

[2] A story about Féchín and the plague is found both in the Latin Life of Saint Gerald of Mayo and in the notes to the hymn Sén Dé (by Colmán of the moccu Clúasaig) in the Liber Hymnorum.

[2] One of Féchín's fellow victims in the plague of 665 is said to have been St Rónán mac Beraig (son of Berach), founder of Dromiskin Monastery: Druim Inesclainn, whose relics were enshrined in 801.

[8] The Uí Chrítáin, a clerical dynasty who claimed collateral descent from Lóegaire, ruled his house between the mid-9th century and 978, and asserted that their eponymous ancestor Crítán was Rónán's grandfather.

The village of St Vigeans, near Arbroath in Angus, has a major collection of early medieval sculpture surviving from a monastery dedicated to the saint, perhaps founded in unrecorded circumstances among the Picts in the 8th century.

A holy well stands among the remains of his monastic community on Omey Island and is a pilgrimage site for those seeking a physical cure for all manner of ailments.