They took them and suffused them with a Christian tenderness, even a Christian forgiveness.

Or they inserted Christian endings, while they left the rest of the stories as pagan as before.

Later on, while the stories were still learned by the bards and recited, they were written down, and somewhat spoiled by a luxurious use of ornamental adjectives, and by the weak, roving and uninventive fancy of men and monks aspiring to literature but incapable of reaching it.
However, in spite of all this intermingling and of the different forms of the same story, it is possible for an intelligent and sensitive criticism, well informed in comparative mythology and folklore, to isolate what is very old in these tales from that which is less old, and that in turn from that which is still less old, and that from what is partly historical, medieval or modern.

This has been done, with endless controversy, by those excellent German, French, and Irish scholars who have, with a thirsty pleasure, recreated the ancient literature of Ireland, and given her once more a literary name among the nations--a name which, having risen again, will not lose but increase its brightness.
* * * * * As to the stories themselves, they have certain well-marked characteristics, and in dwelling on these, I shall chiefly refer, for illustration, to the stories in this book.

Some of these characteristic elements belong to almost all mythological tales, and arise from human imagination, in separated lands, working in the same or in a similar way on the doings of Nature, and impersonating them.
The form, however, in which these original ideas are cast is, in each people, modified and varied by the animal life, the climate, the configuration of the country, the nearness of mountain ranges and of the sea, the existence of wide forests or vast plains, of swift rivers and great inland waters.
The earliest tales of Ireland are crowded with the sea that wrapt the island in its arms; and on the west and north the sea was the mighty and mysterious Ocean, in whose far infinities lay for the Irish the land of Immortal Youth.