From Patrick Joseph Carew's An ecclesiastical history of Ireland:
Of the seminaries founded in the sixth century those of Clonard and Bangor are entitled to particular notice. The establishment at Clonard owes its origin to St. Finnian. In his youth, St. Finnian had been placed under the care of a Bishop by name Fortkern. Having attained to man's estate he left his native country and passing over into Britain became acquainted with David, Gildas and Cathmael, each of whom had then attained a high reputation for sanctity and learning. After the lapse of some time Finnian returned to Ireland. For seven years after his return he employed himself in the study of the sacred Scriptures and in instructing others in the knowledge of them. It was after he had thus attained a high reputation for learning that he formed the monastery of Clonard. His lectures in this new institution were attended by a numerous concourse of students and by many other distinguished persons also who wished to profit by his spiritual advice. In the number of his pupils Finnian reckoned St. Columbkill. (1) In the history of this illustrious Saint we have seen that while his exertions were primarily directed to advance the cause of the Gospel he was not unmindful of the interests of learning. By his influence the Bardic order was rescued from destruction and under his direction the important and useful occupation of transcribing for posterity the learned works of preceding ages was scrupulously attended to by the Monks of Hy. To the Monks of Hy the people of Northumbria owed their conversion to Christianity and also the literary advantages which the institution erected by Aidan at Lindisfarne conferred upon them. Even at the early period we now treat of students began to resort from Britain to Ireland for the benefit of education. Of these Gildas and Petrocus are particularly mentioned by our ancient writers Gildas before he came to Ireland had devoted himself for some years to the cultivation of letters. Wishing however to improve himself still more in philosophy and theology he repaired to Ireland. There his proficiency attracted the attention of his Superiors and he was honoured with an appointment to a professorship in the celebrated school of Armagh. (2) Of Petrocus, from whom Padstow derives its name, we are told that he devoted twenty years in Ireland to the study of general literature and of the sacred Scriptures that he assiduously attended the lectures of masters who were eminent for learning and that he then returned home to distribute to his countrymen the intellectual treasures which he had there acquired.
(1) Besides St. Columbkill two distinguished Ecclesiasticks named Kieran and Columb of Tridaglass studied under St. Finnian. Clonard was devastated by the Danes in 888. It became one of the fixed Sees of Meath in 1118. Duleck became another at the same time. Eugene, Bishop of Clonard, who died in 1194, assumed the title of Bishop of Meath, which has been since retained. In 1206 the See was removed to Newtown. The possessions of the Nunnery of Clonard were confirmed by the Pope in 1195. Another Bishop of the name of Finnian lived in the same century who studied first under Nennio in Britain and afterwards at Rome. This Prelate also founded a religious and literary institution at Moville about the year 540. I may here add that Kieran and Brendan, two pupils of St. Finnian of Clonard, founded two establishments of considerable note the former at Clonmacnois the latter at Birr.
(2) Gildas Britonum historigraphus tunc remanens in Hiberuia sludium regeni et prcedicans in civitate Ardmaca. Caradoc. Vit. Gild.