The tales in which this wizard race figures fall into two well-defined classes. By far the larger portion are heroic sagas, tales that is which describe and exalt the prowess, valour, and cunning of famous champions or chiefs. There are several well-defined cycles of heroic saga in Irish tradition, and their personages are assigned to periods centuries apart. Yet the Tuatha de Danann figure equally in the various cycles—chiefs and champions die and pass away, not they. Undying, unfading, masters and mistresses of inexhaustible delight, supreme in craft and counsel, they appear again and again as opponents and protectors of mortal heroes, as wooers of mortal maidens, as lady-loves of valiant champions. The part they play in these sagas may be more or less prominent, but its character is always secondary; they exist in the story for the convenience of the mortal hero or heroine, to aid in the accomplishment of the humanly impossible, to act as a foil to mortal valour or beauty, to bestow upon mortal champions or princesses the boon of immortal love.
Such is, all too briefly sketched, the nature of this body of romantic fiction. Whoso is familiar with Arthurian romance detects at once an underlying similarity of conception, plot, and incident. In both, specially, does the woman of the immortal race stand before us in clearer outline and more vivid colouring than the man. Nor is the reason far to seek: the mortal hero is the centre of attraction; the love of the fairy maiden who comes from her wonderland of eternal joys lured by his fame is the most striking token and the highest guerdon of his prowess. To depict her in the most brilliant colours is to effectually heighten his glory.
Both these bodies of romantic fiction are in the main variations upon one set of themes—the love of immortal for mortal, the strife or friendly comradeship between hero and god or fairy.
If now we turn back to the living folk-belief of the Irish