Cummian throughout this letter displays the true spirit of a scholar, he humbly apologises for his presumption in addressing such holy men, and calls God to witness that he is actuated by no spirit of pride or contempt for others. When the new cycle of 532 years was first introduced into Ireland he did not at once accept it, but held his peace and took no side in the matter, because he did not think himself wiser than the Hebrews, Greeks, and Latins, nor did he venture to disdain the food he had not yet tasted. So he retired for a whole year into the study of the question, to examine for himself the facts of history, the nature of the various cycles in use, and the testimony of Scripture. There is another book, "De Mensura Pœnitentiarum," ascribed to Cummian and printed in Migne; and there is a poem on his death by his tutor, St. Colman, who was carried off by the same plague a short time after him.[15] The great institution presided over by St. Cummian was flourishing in full vigour at the time of the first incursions of the Northmen. It is frequently mentioned in the Irish Annals as a place of note and learning. Turgesius the Dane, attracted by so fair a booty, promptly plundered and burnt it to the ground. Again and again it was rebuilt, and again and again the same fate befell it. The monastery and the school survived, however, until the coming of the Normans, and the "Four Masters" under the year 1170 record the death of one of its teachers, Cormac O'Lumlini, whom they pathetically designate "the remnant of the sages of Erin," for by this time Clonfert had been six times burnt and four times plundered. Even a greater school, however, than Clonfert, was that founded by St. Ciaran [Keeran], the carpenter's son, beside a curve in the Shannon, at Clonmacnois, not far from Athlone, about the year 544. He had himself been educated by St. Finnian of Clonard, and he died at the early age of thirty-three, immediately after laying the foundations of what was destined to become the greatest Christian college in Ireland.[16]