Cainnech (d. 600/03), son of Luigthech, founder and first abbot of Achad Bó in Osraige (Aghaboe, Co. Laois) and saint in the Irish tradition, probably belonged to the lineage of Corco Dalláin. There are marked difficulties, however, in relation to his ancestry, his early career, and his alleged association with various other saintly figures, including Brendan (qv) of Clonfert, Comgall (qv) of Bangor, and Colum Cille (qv) of Iona. Indeed, Ó Riain has forcefully argued that Cainnech is merely an alias of Colum Cille. Cainnech's pedigree represents him as a son of Luigthech, in turn a son of Lugaid son of Dallán. His mother is named as Mella, a member of Uí Meic Uais, an Airgialla dynasty. She was also the mother of Tigernach of Daire Meille; one foundation of this name was near Lough Melvin, Co. Leitrim, but there was another in the barony of Slievardagh, Co. Tipperary. Alternative versions of Cainnech's pedigree (probably generated by localisations of his cult) attach his lineage to Cianachta Glinne Gaimen or to the Altraige of south-west Munster, to which Brendan of Clonfert belonged. The genealogies place Corco Dalláin in the overkingdom of Ulaid, but it is included among the forslointe (subject peoples), which generally indicates an immigrant population. It is noteworthy that a Munster lineage of Cenél Dalláin, attached to Uí Liatháin, also had ecclesiastical connections; among its members was a certain Gobbán Finn who, significantly, is claimed to have been a son of Lugaid son of Dallán. Coincidentally, at least two other ecclesiastics named Cainnech, who feature in the martyrologies at 31 January and 28 November, have Munster associations. Also, of the seven recorded instances in the published genealogies of Cainnech as a secular name, six relate to Munster and one to Leinster.
The birth of Cainnech is placed at 521 or 527 in the Annals of Ulster. The hagiographers locate his childhood in the midlands. There are hints of a connection with Brega (Co. Meath); his mother's dynasty of Uí Meic Uais had a branch there – as, indeed, had the Cianachta. It may also be significant that according to his Latin Life, Cainnech had a childhood friend named Geal Bregach. There is more emphasis on the west midlands, however, especially on the kingdom of Mide (Co. Westmeath). It happens that Uí Meic Uais was also settled in this area, but concern with Mide perhaps owes more to Uí Néill interest, particularly that of Clann Cholmáin and the rulers of Caílle Follamain, parallel lineages which were in the ascendant by the mid eighth century, when Cainnech's Life was most likely first written. Cainnech, it is claimed, spent his youth at Cemnughe (or Kenn Buge) which, although not positively identified, was probably in Co. Westmeath. Later, as an adult, the saint is said to have encountered the Uí Néill dynast Colmán Bec (qv) in Mide. The hagiographical account is appropriately paralleled by placenames, dedications, and folk tradition in the midland area: for example, in the parish of Kilkenny West, Co. Westmeath, an early church and well are dedicated to Cainnech.
The Latin Life claims that Cainnech studied in Wales under Cadoc (qv) of Llancarvan, and later in the northern marchlands of Leinster under Finnian (qv) of Clonard and Mo-Bí (qv) of Glasnevin. He was ordained priest and, like other early church-founders, developed a practice of withdrawing to deserted places to pray and contemplate. The account of his ensuing career continues the theme of Leinster associations. Before founding his principal church of Aghaboe, it is said that he established a church at Lethdumae (seemingly in the present Co. Kildare), which he afterwards entrusted to an ecclesiastic named Liber. Subsequent episodes of the Life are situated at En Inis (probably in the barony of Forth, Co. Carlow) and at Cluain Brónaig (Clonbrone, parish of Birr, Co. Offaly). According to the same source, he saved the soul of a benefactor named Senach, possibly to be identified with Senach son of Caírthenn of Uí Máil. Other hagiographical data collected in the Book of Leinster hints at further Leinster links; the list of homonymous saints includes a certain Cainnech of Irrus Uí Micáin (apparently in the barony of Forth, Co. Carlow), perhaps an alter ego of the founder of Aghaboe.
Cainnech's Life brings him into contact with several other early church founders including, as already noted, Comgall of Bangor, principal saint of the Dál nAraide. Moreover, the Liber to whom Cainnech entrusted his foundation of Lethdumae is almost certainly identical to Liber (qv), ‘Mo-Libbo moccu Araide’, whose kindred-designation points to Dál nAraide. The close association of Cainnech and Colum Cille in hagiographical tradition prompts many questions. Central to the difficulty is the marked overlap in their respective spheres of cult dissemination, and the scope for confusion arising from their similar hypocoristic name-forms Mo-Chainne and Mo-Chonna. While Colum Cille features in the Latin Life of Cainnech, the latter is mentioned several times in Adomnán's late seventh-century ‘Vita Columbae’ (i, 4; ii, 13–14; iii, 17). For instance, the Life relates a curious incident (ii, 13) in which Colum Cille telepathically communicated to Cainnech that he himself was in danger at sea, whereupon Cainnech rushed out of the refectory (where he was blessing the bread for a communal meal) to pray for Colum Cille's safety. This has been interpreted as a recollection of an actual event passed on to Adomnán (qv), who also relates that Cainnech later visited Iona and celebrated the Eucharist with Colum Cille.
Besides, it is possible that, as claimed by the Life of Comgall (§18), Cainnech accompanied Colum Cille on his visit to King Bruide at Inverness. This is not mentioned by Adomnán, but it may have been because he did not wish to deprive Colum Cille of the exclusive honour of having converted the Picts, and so did not name his companions. There is, presumably, some basis for the traditions which associate Cainnech with missionary activity in Scotland; certainly, his cult became established there at an early date. A church called Cill Chainnich formerly stood on Iona – its site, in the modern period, marked by a cemetery. There are well established church dedications to Cainnech at Inchkenneth on Mull, at Cambuskenneth below Stirling, and at Kilchennich on Tiree. He is credited with the foundation of the first church at Rigmonaig (now St Andrews), his chief Scottish foundation. His feast-day is still observed in the dioceses of St Andrews and Argyll.
In Ireland, his cult was disseminated in the midlands and in Leinster. Liber and some of the churches associated with him were later claimed by Glendalough, which enjoyed the political patronage of Uí Máil at least from the second half of the seventh century onwards; this development may explain the presence of Cainnech in the Latin Life of St Cóemgen (qv). Similarly, a cult of Cainnech developed in the north, centred on Drumachose, Co. Londonderry, which perhaps explains the genealogical link with the Cianachta, given the recognised tendency to localise the cults of saints and to manipulate their pedigrees in the interest of prominent local kindreds.
Of all the foundations ascribed to Cainnech, however, the most famous is Aghaboe, which is denoted his principal church (prímchell) in the glosses in two manuscripts of the Martyrology of Óengus (qv) (fl. c.830) and in the Martyrology of Gorman (Máel Muire Ua Gormáin (qv)). There are three versions of his Latin Life, which (although written at least a century-and-a-half after his death) is of considerable historical interest. A poem for the feast-day of Cainnech (‘Cainnech mo chomarci’) is attributed to Colum Cille; with considerably less probability a poem in honour of Colum Cille (‘Guidium mac Feidelmid’) is attributed to Cainnech.
The year of Cainnech's death is variously given as 600 or 603. Presumably he died on 11 October, under which date he is commemorated in the martyrologies. Various attempts were made at estimating his age at death; according to some sources (Mart. Tall.; Ann. Tig.), he lived to be 84 or 87, although the post-factum notices of his birth in the Annals of Ulster imply a lifespan of 73 to 79 years, which seems more plausible. His successor at Aghaboe was Liber.