Catholic Encyclopedia (1913)/School of Derry
This was the first foundation of St. Columba, the great Apostle of Scotland, and one of the three patron saints of Ireland. When a terrible plague, known as the Buidhe Connaill or the Yellow Plague, dispersed the monks of the monastery of Glasnevin in the year 544, Columba instinctively turned his footsteps towards his native territory, and, full of the spirit of monasticism, bethought himself of founding his first monastery there, amongst his own kith and kin. An excellent site of 200 acres was offered to him by his princely cousin, Aedh, son of Ainmire, and the necessary permission of his master, St. Mobhi Clarainech, given with his dying breath, was immediately forthcoming. And so, a few miles from Ailech, "the stone-hill fortress of the Hy-Neill", and close beside a beautiful oak grove which gave the place its name - Doire Colgaigh, or the oak wood of Colgagh - Columba built his church and several cells for his first monks and disciples. This, according to the "Annals of Ulster", was in the year 545 (correctly, 546). Students both clerical and lay flocked hither from all sides attracted by the immediate fame of the new school, and the character of its founder. For several years Columba himself guided its destinies, and then, in pursuance of his apostolic vocation, he left to establish and govern the second of his great schools amid the oak woods of Durrow in the King's County. But whether in Derry or away from it, in Durrow or Kells, or in distant Iona, the saint's heart was ever with his first foundation, and often in the tenderest poetry he poured out his love for "My Derry, mine own little grove", with its "crowds of white angels from one end to the other".
For centuries after Columba's death the School of Derry continued to flourish, and in the twelfth century, it was said to be the most important of the Columban foundations in Ireland. To this period, the most glorious of its history, belong the names of several members of the illustrious family of Brolchain - saints, scholars, and builders - as well as that of the illustrious Gelasius, successor of St. Malachy in the primacy of Ireland. Like all similar institutions it suffered severely from the ravages of the Danes. It survived these, to disappear completely, however, in the general devastation of monasteries that took place in Ireland in the sixteenth century. (See COLUMBA, SAINT.)
ADAMNAN, Vita Columbæ, ed. FOWLER (London, 1895); WHITLEY STOKES, Lives of Saints from the Book of Lismore, in Anecdota Oxonien (Oxford, 1890), V; HEALY, Ireland's Ancient Schools and Scholars (Dublin, 1890).