It is these four: the Black Book of Caermarthen; the Book of Aneurin; the Book of Taliessin; and the Red Book of Hergest, that are here termed the four ancient books of Wales, and it is with the ancient poems contained in these four books that we have now to do. Undoubtedly it is in these four books that the most ancient. texts of the poems are to be found. The contents of these books remained little known till the publication of the Archaeologia...