The Senchus Mor has until now been our main source for information about conditions in ancient Ireland. It is a collection of ancient legal decisions which, according to the later composed introduction, was compiled on the orders of St. Patrick, and with his assistance brought into harmony with Christianity, rapidly spreading in Ireland. The High King of Ireland, Laeghaire (428-458, according to the Annals of the Four Masters), the Vice-Kings, Corc of Munster and Daire, probably a prince of Ulster, and also three bishops: St. Patrick, St. Benignus and St. Cairnech, and three lawyers: Dubthach, Fergus and Rossa, are supposed to have formed the commission which compiled the book and there is no doubt that they did their work more cheaply than the present commission, who only had to publish it. The Four Masters give 438 as the year in which the book was written. The text itself is evidently based on very ancient heathen materials. The oldest legal formulas in it are written in verse with a precise metre and the so-called consonance, a kind of alliteration or rather consonant assonance, which is peculiar to Irish poetry and frequently goes over to full rhyme. As it is certain that old Irish law-books were translated in the fourteenth century from the so-called Fenian dialect (Berla Feini), the language of the fifth century, into the then current Irish (Introduction (Vol. 1), p. xxxvi and following) it emerges that in the Senchus Mor too the metre has been more or less smoothed out in places; but it appears often enough along with occasional rhymes and marked consonance to give the text a definite rhythmical cadence. It is generally sufficient to read the translation in order to find out the verse forms. But then there are also throughout it, especially in the latter half, numerous pieces of undoubted prose; and, whereas the verse is certainly very ancient and has been handed down by tradition, these prose insertions seem to originate with the compilers of the book. At any rate, the Senchus Mor is quoted frequently in the glossary composed in the ninth or tenth century, and attributed to the King and Bishop of Cashel, Cormac, and it was certainly written long before the English invasion. All the manuscripts (the oldest of which appears to date from the beginning of the 14th century or earlier) contain a series of mostly concordant annotations and longer commenting notes on this text. The annotations are in the spirit of old glossaries; quibbles take the place of etymology and the explanation of words, and comments are of varying quality, being often badly distorted or largely incomprehensible, at least without knowledge of the rest of the law-books. The age of the annotations and comments is uncertain. Most of them, however, probably date from after the English invasion. As at the same time they show only a very few traces of developments in the. law outside the text itself, and these are only a more precise establishment of details, the greater part, which is purely explanatory, can certainly also be used with some discretion as a source concerning earlier times. The Senchus Mor contains: From this we obtain much valuable information on the social life of that time, but, as long as many of the expressions are unexplained and the rest of the manuscripts is not published, much remains dark. In addition to literature, the surviving architectural monuments, churches, round towers, fortifications and inscriptions also enlighten us about the condition of the people before the arrival of the English.
Marx Engels on Art and Literature