The manuscript materials for ancient Irish history may be divided into two classes: the historical, which purports to be a narrative of facts, in which we include books of laws, genealogies, and pedigrees; and the legendary, comprising tales, poems, and legends. The latter, though not necessarily true, are generally founded on fact, and contain a mass of most important information, regarding the ancient customs and manner of life among our ancestors. For the present we must devote our attention to the historical documents. These, again, may be divided into two classes--the lost books and those which still remain. Of the former class the principal are the CUILMENN, _i.e._, the great book written on skins; the SALTAIR OF TARA; the BOOK OF THE UACHONGBHAIL (pron. "ooa cong-wall"); the CIN DROMA SNECHTA; and the SALTAIR OF CASHEL. Besides these, a host of works are lost, of lesser importance as far as we can now judge, which, if preserved, might have thrown a flood of light not only upon our annals, but also on the social, historical, and ethnographic condition of other countries. The principal works which have been preserved are: the ANNALS OF TIGHERNACH (pron. "Teernagh"); the ANNALS OF ULSTER; the ANNALS OF INIS MAC NERINN; the ANNALS OF INNISFALLEN; the ANNALS OF BOYLE; the CHRONICUM SCOTORUM, so ably edited by Mr. Hennessy; the world-famous ANNALS OF THE FOUR MASTERS; the BOOK OF LEINSTER; the BOOK OF LAWS (the Brehon Laws), now edited by Dr. Todd, and many books of genealogies and pedigrees.
For the present it must suffice to say, that these documents have been examined by the ordinary rules of literary criticism, perhaps with more than ordinary care, and that the result has been to place their authenticity and their antiquity beyond cavil.
Let us see, then, what statements we can find which may throw light on our early history, first in the fragments that remain of the lost books, and then in those which are still preserved.
The CUILMENN is the first of the lost books which we mentioned. It is thus referred to in the Book of Leinster:[2] "The _filés_ [bards] of Erinn were now called together by _Senchan Torpéist_ [about A.D. 580], to know if they remembered the _Táin bó Chuailgné_ in full; and they said that they knew of it but fragments only. Senchan then spoke to his pupils to know which of them would go into the countries of _Letha_ to learn the _Táin_ which the _Sai_ had taken 'eastwards' after the _Cuilmenn_. Eminé, the grandson of Nininé, and Muirgen, Senchan's own son, set out to go to the East."