Tallaght in the barony of Newcastle and five miles from Dublin. St. Maelruan, was abbot and bishop of Tallaght, is reckoned among the learned men of his age and probably was the first among the authors of the Martyrology of Tallaght. Among his disciples for several years was Aengus the great Hagiologist. St Maelruan died on the 7th of July, AD 788. Here another bishop resided within five miles of Dublin
AD 824 Saint Aengus was abbot. This celebrated saint was of an illustrious family descended from the ancient princes of Dalaradia in Ulster. His father was Aengaven, son of Hoblen, hence Aengus is distinguished by that surname. He embraced the monastic state in the convent of Clonenagh under the holy abbot Moetlagen and made great progress in piety and learning. He was accustomed to spend a great part of the day in a lonesome spot not far distant from the monastery, called after him Diseart Aengus, where he was engaged in reading the Psalms and in constant prayer.
His reputation for sanctity becoming very great. He wished to withdraw to some place in which he would be unknown. Having heard of the strict and exemplary discipline with which St. Maelruan governed his monastery, he resolved to put himself under his instruction and guidance. When arrived at the monastery of Tallaght, Aengus concealed his name and his rank in the Church and requested to be received as a novice. It is said that he was employed seven years in the most laborious avocations, and his humility and the austerity of his life were so remarkable that he was called Celle Dhia, i.e., the servant or companion of God.
At length his rank and acquirements were discovered by St. Maelruan in consequence of his having assisted one of the school boys of the monastery in preparing his task at which he had been either dull or negligent and who was afraid of being punished by St. Maelruan. The boy hid himself in the barn where Aengus was working and who taking compassion on the youth assisted him so well that he was enabled to recite his task to the satisfaction of his master. Surprised at the change of his pupil, Maelruan pressed him to tell how it came to pass and compelled him to relate the whole circumstance, although Aengus desired him to be silent on the matter. Maelruan, who had hitherto considered Aengus as an illiterate rustic, repaired to the barn and embracing him complained of having concealed his name and expressed his deep regret for the humble and abject manner with which he had been treated. Aengus prostrating himself at the feet of the holy abbot begged pardon for what he had done.
Henceforth, he was regarded with the greatest consideration and it is probable that he remained at Tallaght until Maelrnan's death in 788. He must then have succeeded to the abbacy of Tallaght. He became afterwards the abbot of Clonenagh. He was also raised to the episcopal rank without leaving the monasteries which he governed. Aengus died on the 11th of March but in what year is not recorded and was buried at Clonenagh.
Besides the martyrology of Tallaght, he composed another work on the saints of Ireland divided into five small books, the first containing the names of three hundred and forty five bishops, two hundred and ninety nine priests and abbots and seventy eight deacons, the second entitled the Homonymous or saints of the same name as Colman &c., the thirdm the book of sons and daughters, giving an account of holy persons born of the same parents, the fourth giving the maternal genealogy of about two hundred and ten Irish saints, and the fifth, a collection of litanies in which are invoked groups of saints among whom are included several foreigners who died in Ireland. In this litany he specifies the very places in which they are interred...
In addition to the evidence which this litany supplies of the ancient fame and sanctity of Ireland and of the esteem and veneration with which the natives of other countries regarded our isle as the asylum of piety and learning and hospitality, there are all over the country monumental inscriptions which evidently demonstrate the truth which the litany of Aengus unfolds. And, although Ireland converted myriads in the sister isle and afforded hospitality to her princes and to her ascetics, still England and England alone, and wherever she has planted the false tenets of her heretical doctrines, the name of Ireland and of Irishmen is despised. While, all over the continent of Europe, Ireland and her people are revered and respected. English, Roman, Italian, Gallic and even Egyptian saints seven in number are recounted in the litany of Aengus.
Another work of his a poetical one comprises the history of the Old Testament, which he put into the form of prayers and praises to God.
AD 889 died St. Dichull. There was an abbot of Louth of this name of whom St. Patrick is said to have prophesied.
AD 937 died Laidgene comorb of Ferns and Tamlacht.
AD 964 died Cronmalius, professor of this abbey
AD 1125 died Maelsuthumius another professor.