It is thus apparent that the Irish writers possessed ample means of becoming acquainted with the traditions, both oral and written, of the Greek and Eastern Churches. The knowledge thus acquired extended to the Apocalyptic Visions referred to in the preceding section, as is proved by internal evidence furnished by the Irish Visions, both by way of direct reference, and by the nature of their contents. It remains to see how far the predilection which the Irish writers manifested for this class of literature, and the special characteristics which it assumed in their hands, may have been determined by their familiarity with analogous ideas already existing in their national literature. At the period in question, the traditional literature of Ireland would appear to have entered into the national life to no less a degree than in Greece itself. Indeed, in certain respects, it was still more closely interwoven with the habits of the people and the framework of society than in Greece, for the literary profession was provided for by a public endowment, something like that of an established National Church, and its professors constituted a body organised by law, and occupying a recognised position in the State. One of the most marked characteristics of early Irish civilisation, in its every branch, was an exaggerated tendency towards symmetrical classification and multiplicity of detail. This tendency extended to the social system, and the earliest records of ancient Ireland that have come down to us show that society was arranged according to a very elaborate scheme of ranks and classes,[100] among which the literary profession was remarkable alike for the number of its members, and for the consideration in which they were held. It was divided into several distinct orders, each of which was specially addicted to its own department of study, and of these the place of greatest honour and dignity belonged to the Filid, who combined with other functions the special duty of preserving and transmitting the national traditions.[101] The order of the Filid was further subdivided into seven ranks or degrees, graduated according to the attainments which their respective members were required to possess. For all, however, a knowledge of the romantic literature of their country was an indispensable qualification--the Árd-Ollamh, the chief of the order, being required to know two hundred and fifty _prím-scéla_, or principal stories, and one hundred of secondary importance; and so on in a descending scale through the inferior degrees of the literary hierarchy. These tales, in turn, were likewise grouped, with all the precision of a scientific classification, according to their subject-matter.[102] Two lists are extant giving the titles of the several kinds; the elder, preserved in the Book of Leinster, is ascribed by M. d’Arbois de Jubainville to the seventh century, or, at latest, the beginning of the eighth century. They are classed under the