MANUSCRIPT SOURCES FOR CELTIC RELIGION
In terms of exploring and understanding Celtic mythology and religion, the manuscript traditions of Ireland and Wales give the most detailed insights. The most important Irish sources are Lebor na hUidre (The Book of the Dun Cow) from before 1106, containing texts from the so-called Mythological Cycle, which gives a range of pseudo-historical accounts of successive invasions of Ireland, and the Ulster Cycle, which centres around the traditional heroes of Ulaid in what is now Ulster; Lebor Laignech (The Book of Leinster), compiled after 1150, containing the Dindshenchas, which is a collection of Old Irish local legends relating to place-names and landscape features, as well as texts from the Ulster Cycle and other important mythical and legendary material; and Lebor Gabala Erenn (The Book of the Takings of Ireland) from the twelfth century, which is a collection of pseudo-historical texts, among these some pertaining to the Mythological Cycle.
Several other manuscripts also exist. Of the Welsh sources, writings record the traditions, but not the beliefs. Nor can it be altogether refuted that these learned men may have had access to some of the classical writings on the Celts and that this may have influenced their views in some ways, which is a tremendously interesting point to reflect on: that the scribes may have employed some of the same classical sources as we do, and that they may have done so in similar attempts to understand the spiritual life of their ancestors. Although linguistic evidence in the manuscripts shows that some texts go back to the tenth century CE it would be naive to think that they had completely escaped editing and revision in later times, as Morten Warmind also points out: “Undoubtedly very much of the material in the stories was orally transmitted, ancient, and reflects Celtic religion, but the versions we have today were as irrefutably written down by a conscious author with a contemporary audience in mind” (ibid.: 219).It therefore seems a sensible approach to avoid the extremes of either discarding the vernacular literature altogether on account of its lateness or, alternatively, taking it as reflecting an undiluted pre-Christian tradition. Neither extreme would get us anywhere. What is needed is a qualified sifting of the literary evidence which will enable us to discover which aspects of it can be corroborated by Continental evidence and can therefore be regarded as more broadly Celtic and which aspects are found only in the insular literature and must therefore be regarded as specifically Irish or Welsh features, respectively. It is obviously impossible here to present any exhaustive account of the situation as a whole.