Formation and Education
Cainnech received his monastic and scholarly formation in the foremost schools of sixth-century Ireland and Britain. In 543 he entered the monastic school of Finnian at Clonard, the community from which the Twelve Apostles of Ireland took their name; the following year, in 544, he studied under Mobhí Clárainech at Glasnevin alongside Kieran (Ciarán) of Clonmacnoise and Comgall.
In 545 he was ordained priest at the monastery of Llancarfan in Wales, associated with Saint Cadoc. By 550 he had travelled to Rome and obtained a papal blessing before returning to his native Glengiven, where he converted his foster brother Geal-Breagach and founded the monastery of Drumachose in Limavady.
Mission in Scotland
From about 565 Cainnech joined Columba on Iona, and his name is preserved across a number of Scottish place-names and foundations. He is credited with building a church at Saint Andrews, establishing monastic cells on the island of Ibdon (possibly identified with South Uist), founding an oratory called Lagan-Kenny on the shores of Loch Laggan, and establishing a monastery in Fife on the banks of the River Eden.
Places bearing his memory include Kil-Chainnech on Tiree, a burial ground on Iona, and Inch Kenneth off the coast of Mull. Adomnán's Vita Columbae records his association with Columba during these years.
Aghaboe and Kilkenny
Returning to Ireland, Cainnech received land grants from King Colmann, son of Feradach, among them Aghaboe — 'the field of the Ox' — in County Laois, which became his principal monastery. Around 597 he is associated with founding a monastery near the site of the present Saint Canice's Cathedral in Kilkenny.
Aghaboe remained a centre of learning after his death; in the seventh century it sent out the missionary Feargal, known as Vergilius of Salzburg, to Austria. Cainnech was regarded as co-patron of Kilkenny and of the historic kingdom of Osraige, together with Ciarán of Saigir.
Scholarship and Writings
In old age, while staying on an island in the former Loch Cree, Cainnech is said to have written a commentary on all four Gospels. Known as 'Glass Kinnich' or the 'Chain of Cainnech,' this work became a standard medieval Gospel commentary and was preserved in his church.
Legacy and Relics
Cainnech is counted as the twelfth of the Twelve Apostles of Ireland, the disciples of Finnian of Clonard. He was venerated as the patron of the shipwrecked and as co-patron of Kilkenny and the kingdom of Osraige.
His relics were destroyed in 1346 when Diarmaid Mac Giollaphádraig burned the abbey of Aghaboe. His feast is kept on 11 October in both the Roman Catholic and Eastern Orthodox traditions; Eastern Orthodox sources also record commemorations on 1 and 14 August.
