Ailbe (d. 527?), patron of the church of Imlech Ibair (Emly, on the Limerick/Tipperary border), Munster's most important church till it was superseded by Cashel in the early twelfth century, was Munster's premier saint, whence the saying Mumu uili . . . iar cúl Ailbe, ‘all Munster . . . behind Ailbe’ (Ó Riain, Corpus geneal. SS Hib. (1985), §729.3). With the establishment of dioceses in the early twelfth century, the saint was adopted as patron of the archdiocese of Cashel and Emly. Despite being referred to as alter Patricius, ‘a second St Patrick’ (Heist, Vitae SS Hib., 118), Ailbe – whose real origins are quite obscure and probably pre-Christian – came to rank among the so-called pre-Patrician saints who, apparently due to Munster pretensions to ecclesiastical primacy, were held to have already evangelised the south of Ireland before the mission of St Patrick (qv).
In fact, much of the saint's record reflects southern ecclesiastical politics. His parents are named as Olcu and Sant, and his pedigrees variously attach him to the Daulraige and Táecraige, both of which were hereditary ecclesiastical families at Emly, with a remote descent from the Dál nAraide of Ulster. This descent was based, no doubt opportunistically, on the similarity between the names Dál nAraide and Araid, which was used of the tribal territory about Emly. The saint's Life, which survives only in Latin versions, likewise assigns to him a visit to Dál nAraide, where he is said to have founded his first church. The version of the saint's Life in the ‘Codex Salmanticensis’ (Heist, Vitae SS Hib., 118–31) forms part of the so-called group of O'Donohue Lives, which, on mainly orthographical grounds, Sharpe (Medieval Irish saints' Lives, 329) would date 750–850. As Sharpe concedes (ibid., 320), names do not provide the most reliable dating criteria, and the issues underlying the Lives comprising the group have yet to be identified adequately.
Because of the important role played by the churches associated with him – first Emly, then Cashel – Ailbe figured prominently in other saints' Lives, at home and abroad. The circuit of Munster by Patrick, as reported in the ninth-century Tripartite Life, brought the Armagh saint to Emly, where he is said to have involved Ailbe in a miracle performed by himself. Rhygyfarch, the late eleventh-century biographer of David of Menevia, who was probably aware of the leading role of Ailbe's successors in the the preparations for the twelfth-century reform in Ireland, assigned to Ailbe, ‘bishop of Munster’, the symbolically important task of baptising David (Wade-Evans, 153, §7). For his part, Ailbe's biographer attributed to his subject a prophecy of David's sanctity while the latter was still in his mother's womb, borrowing in the process a motif that occurs elsewhere in Rhygyfarch's Life of David. The monks of the Schottenklöster in Germany and Austria, who were predominantly recruited in Munster, also took cognisance of Ailbe's cult and, germanicising his name as Albert, compiled for him a new Life. In this guise the saint was brought back to Ireland, to join Ailbe as co-patron of the archdiocese of Cashel and Emly. His principal feast-day is 11 September.