AILERAN (Aileranus, Aleranus, Aireanus, Ereanus), called the Wise, saint. — Little is known of his life. He was a monk at Clonard (v.) and, it seems, from 650 onwards he directed that school. Bellesheim judges him one of the “most representative doctors” of Ireland in the 7th century. He died in 664 or 665. The Martyrology of Oengus (v.) commemorates him on 29 December.
There survives from him an *Interpretatio mystica Progenitorum Christi*, interesting also for the knowledge it provides of the books that made up the monastic libraries of Ireland (St Jerome, Origen, Arnobius, Philo, Flavius Josephus, etc.). It sets forth the traditional interpretation; from his manner of expression, he shows himself ignorant of Hebrew.
The pamphlet, supplemented by the *Moralis explanatio eorum nominum*, was published, from a codex of St Gall, by the Minorite Patrick Fleming, at Louvain (1667), together with the works of St Columbanus. Later inserted in the *Bibliotheca maxima Patrum* of Lyons (1677, XII, pp. 37-41), it was reproduced in PL 80, 327-42. But this edition is incomplete. Charles Mac Donnel, in *Proceedings of the Royal Irish Academy* (7 [1857-61], pp. 369-71), published the missing portion from a manuscript in the Imperial Library of Vienna (Cod. theol., 119) which contains an unpublished work of Sedulius Scottus (v.), the *Collectaneum in Matthaeum*.
The poem known as the *Canon Evangeliorum* (i.e., in ten canons of Eusebius, or the harmony of the four Evangelists), once reckoned among the poetic compositions of Alcuin (PL 101, 729), must be assigned to Aileran, as De Bruyne has shown, chiefly on the basis of codex Barberin. 587.
Colgan (*Acta Sanctorum Hiberniae*, Louvain 1645, p. 140) attributes to Aileran three lost lives of saints: of Brigid of Kildare, of Patrick, and of Fechin of Fore.
Eugene O’Curry (*Irish Ecclesiastical Record*, 1 [1864], pp. 63-64) published, with an English translation, a prayer in Gaelic attributed to Aileran in the Yellow Book of Lecan, which preserves the text.
A work entitled *Rethorica Alerani* (sic), which may have been one of his grammatical works, was in the 11th century in the monastic library of St Florian, near Linz.