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.  Between its shining shores and Ireland, strange islands—­dwelt in by dreadful or by fair and gracious creatures, whose wonders Maeldun and Brendan visited—­lay like jewels on the green and sapphire waters.  Out of this vast ocean emerged also their fiercest enemies.  Thither, beyond these islands into the Unknown, over the waves on a fairy steed, went Oisin with Niam; thither, in after years, sailed St Brendan, till it seemed he touched America.  In the ocean depths were fair cities and well-grassed lands and cattle, which voyagers saw through water thin and clear.  There, too, Brian, one of the sons of Turenn, descended in his water-dress and his crystal helmet, and found high-bosomed maidens weaving in a shining hall.  Into the land beneath the wave, Mananan, the proud god of the sea brought Dermot and Finn and the Fianna to help him in his wars, as is told in the story of the Gilla Dacar.  On these western seas, near the land, Lir’s daughters, singing and floating, passed three hundred years.  On other seas, in the storm and in the freezing sleet that trouble the dark waves of Moyle, between Antrim and the Scottish isles, they spent another three centuries.  Half the story of the Sons of Usnach has to do with the crossing of seas and with the coast.  Even Cuchulain,