Tighernach, Abbot of Clonmacnoise, historian and annalist, lived in the 11th century. O' Curry says his "name stands among the first of Irish annalists … If we take into account the early period at which he wrote, the variety and extent of his knowledge, the accuracy of his details, and the scholarly criticism and excellent judgment he displays, we must agree … that not one of the countries of northern Europe can exhibit a historian of equal antiquity, learning, and judgment." O'Donovan says: "His quotations from Latin and Greek authors are numerous; and his balancing their authorities against each other manifests a degree of criticism uncommon in the iron age in which he flourished. He quotes Eusebius, Orosius, Julius Africanus, Bede, Josephus, St. Jerome, and others." Eight copies or fragments of his annals are known to exist; but no one of them is perfect. Two are in the Bodleian Library at Oxford; two in the Royal Irish Academy; one in Trinity College; two in the British Museum; and one in the library of the Earl of Ashburnham. Professor O'Curry gives a minute account of these manuscripts. Tighernach died in 1088, and was buried at Clonmacnoise.