From Thomas Walsh's History of the Irish Hierarchy chapter lx, p. 646 ff:
Drumcliffe, in the barony of Drumcliffe, formerly a town of some note.
Lanigan is not inclined to assign to St. Columbkille the merit of erecting the monastery of Drumcliffe; he is only willing to admit, as he does with regard to St. Fechin, at Ballysadare, that St. Columba only founded a church in this place. At the time in which not only Columba flourished, but also that in which St. Fechin was cut off by the plague, the erection of a monastery was a work of very little delay, especially when the people or the prince were pleased to sanction and assist in its construction. The Abbé MacGeoghegan writes, that the piety of the early Christians of Ireland was such, that they not only gave food and other necessaries for the wants of their religious houses, but even dedicated some of their families to the service of God, as was the custom with the Jewish people. If the history of the foundation of Imay, Co. Galway, be correct, we are therein assured, that the holy founder was at his monastery in Easdara, when admonished to seek the island of Imay, by an angel, — yet Lanigan will not accord to him the erection of that establishment. A St. Thorian, a disciple of Columba, who followed him afterwards to Hy, is named as having governed Drumcliffe,
as the first abbot. It is again argued, that as a blank occurs in the names of the abbots, until the year 921, St. Columba was not the founder. Drumcliffe does not appear to be singular in this respect. Voids of the same sort occur in the succession of the bishops of our sees. Lanigan also urges the silence of Ware with regard to its foundation, &c. Ware is also silent of the Dominican convent of Clonmel, one of far later date. Ware omits the ancient monastery of Tirdaglas, founded by Columba, son of Crimthan.
A.D. 921, died the abbot of Drumcliffe, St. Thorian or Thorannan. He was also abbot of Banchor, and was honored on the 12th of June. Died also this year the blessed Maolpatrick Mac Moran.
A.D. 930, died the abbot Moyngall, son of Becan.
A.D. 950, died the blessed Flan O'Becain, archdeacon of Drumcliffe, a learned and celebrated scribe.
A.D. 1029. This year Aengus O'Hoengusa, archdeacon of Drumcliffe, with sixty other persons, perished by an accidental fire in an island called Inislanne (territory of Carberry).
A.D. 1053, Murchad O'Beollain, archdeacon of Drumcliffe, died.
A.D. 1077, died Murrogh O'Beollan, comorb of Drumcliffe and St. Columb.
A.D. 1187, the abbey was spoiled by Melaghlin, king of Meath. The wrath of Heaven soon overtook him, having been killed in a fort-night after.
A.D. 1225, died Amlave O'Beollain, archdeacon of Drumcliffe, a man of extraordinary erudition, and in general esteem for piety, wisdom, and unbounded hospitality.
A.D. 1252, died in this abbey Maelmaidoc O'Baollan, comorb of St. Columb, a venerable and hospitable man, and in universal estimation in England and Ireland.
A.D. 1416, this abbey was set on fire by a band of plunderesr; the abbot Maurice O'Coincoil perished in the flames.
A.D. 1503, died the abbot O'Beollan.