Man makes his gods in his own image, and the doctrines of omen, coincidence, and correspondence helped by incessant and imperfect observation and logic, bring about a system of religious observance, of magic and ritual, and all the masses of folly and cruelty, hope and faith, and even charity, that group about their inventions, and seem to be the necessary steps in the onward path of progressive races.
When to these we add the true and exaggerated memories of actual heroes, the material before the student is pretty completely comprised.

Though he must be prepared to meet the difficulties caused in the contact of races, of civilisations, by the conversion of persons holding one set of mythical ideas to belief in another set of different, more attractive, and often more advanced stage.
The task of arriving at the scientific, speculative ethic, and the actual practice of our remote ancestry (for to that end is the student of mythology and folk-lore aiming) is not therefore easy.

Nor is the record perfect, though it is not so poor in most cases as was once believed.

The Brothers Grimm, patriarchs alike as mythologists and folk-lorists, the Castor and Pollox of our studies, have proved this as regards the Teutonic nations, just as they showed us, by many a striking example, that in great part folk-lore was the mythology of to-day, and mythology the folk-lore of yesterday.
In many cases we are helped by quite modern material to make out some puzzle that an old tale presents, and there is little doubt but that the present activity in the field of folklore will not only result in fresh matter but in fresh methods freshly applied.
The Scandinavian material, at all events, is particularly rich: there is the extensive Icelandic written literature touching the ninth and tenth and eleventh centuries; the noble, if fragmentary remains of Old Northern poetry of the Wickingtide; and lastly, the mass of tradition which, surviving in oral form, and changing in colour from generation to generation, was first recorded in part in the seventeenth, and again in part, in the present century; and all these yield a plentiful field for research.

But their evidence gains immensely by the existence of Saxo's nine books of traditional and mythic lore, collected and written down in an age when much that was antique and heathen was passing away forever.
The gratitude due to the Welshman of the twelfth century, whose garnered hoard has enriched so many poets and romances from his day to now, is no less due to the twelfth-century Dane, whose faithful and eloquent enthusiasm has swept much dust from antique time, and saved us such a story as Shakespeare has not disdained to consecrate to highest use.